fix job control on FreeBSD and macOS: do not use WCONTINUED

Go's syscall.WaitStatus decodes the "continued" status wrongly on BSD:
on FreeBSD it is read as killed by SIGCONT, so after bg the job was
reported as "Exit 147" and removed from the job table while it was
still running (fg: "no such job"); on macOS it is read as stopped.

The shell marks jobs as running itself when it continues them, so wait4
is called without WCONTINUED and only exited/signaled statuses finish a
process.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -12,6 +12,13 @@ Built-in commands:
   quit [code]   - Quit shell with status code (default: $?)
   set VAR=val   - Set environment variable
   export VAR=val - Export environment variable
+  source file   - Run the commands of file in this shell (also: . file)
+  jobs          - List background and stopped jobs
+  fg [%n]       - Continue job n (default: current job) in the foreground
+  bg [%n]       - Continue stopped job n in the background
+  wait [%n]     - Wait for job n or all background jobs
+  alias [name[=value] ...] - Define or show aliases (alias ll='ls -l')
+  unalias name  - Remove an alias (unalias -a: all aliases)
   help          - Show this help
 
 Features:
@@ -23,6 +30,9 @@ Features:
     override with $GOSH_HISTFILE); lines starting with a space are not saved
   - Tab completion for commands and file paths
   - Tilde expansion (~, ~/path) at the start of unquoted words
+  - Wildcards: * ? [abc] [a-z] [!abc] match file names (not hidden files
+    unless the pattern starts with a dot); quoted wildcards and values of
+    variables are not expanded, a pattern without match is kept as is
   - Colored prompt (user@host green, red for root; directory blue),
     configurable with $GOSH_COLORS, e.g. GOSH_COLORS='user=1;33:path=36'
     (keys user, root, path; values are ANSI SGR codes, empty = no color);
@@ -33,16 +43,23 @@ Features:
     a || b (b only if a failed); $? is the exit status of the last command
   - Pipes (a | b) and redirections: < file, > file, >> file, 2> file,
     2>> file, 2>&1, >&2, &> file (stdout and stderr), &>> file
+  - Job control: command & runs in the background, Ctrl+Z stops the
+    foreground job; jobs, fg, bg and wait manage the jobs
+  - Aliases replace the first word of a command in interactive shells
+    (define them in ~/.goshrc); \name or 'name' skips the alias
   - Non-interactive use: gosh -c 'command', gosh script, command | gosh;
     the exit status is the one of the last command
+  - Startup files: login shells (-l or argv[0] starting with -) read
+    /etc/gosh/profile and ~/.gosh_profile, interactive shells read
+    /etc/gosh/goshrc and ~/.goshrc (skip with --noprofile, --norc)
 
 ```
 
 ### Aufruf
 
 ```
-gosh [-l] [-i] [script]
-gosh [-l] -c command
+gosh [-l] [-i] [--norc] [--noprofile] [script]
+gosh [-l] [--noprofile] -c command
 gosh -version
 ```
 
@@ -53,12 +70,54 @@ gosh -version
 | `gosh skript.gosh`     | führt das Skript Zeile für Zeile aus                             |
 | `befehle \| gosh`      | liest die Befehle von stdin                                      |
 | `-i`                   | erzwingt den interaktiven Modus, auch ohne Terminal              |
-| `-l`, `--login`        | Login-Shell (wird akzeptiert, eine Startdatei gibt es noch nicht) |
+| `-l`, `--login`        | Login-Shell, liest die Profil-Dateien (siehe unten)              |
+| `--norc`               | `goshrc`-Dateien nicht lesen                                     |
+| `--noprofile`          | `profile`-Dateien nicht lesen                                    |
 
 Ohne Terminal bricht gosh bei einem fehlgeschlagenen Befehl nicht ab und beendet sich mit dem Exit-Status des letzten Befehls: `127`, wenn ein Befehl nicht gefunden wurde, `126`, wenn er nicht ausführbar ist, `128+n`, wenn er durch Signal `n` beendet wurde. Leere Zeilen und Zeilen, die mit `#` beginnen, werden übersprungen, Skripte können also mit `#!/usr/bin/gosh` beginnen.
 
 Damit funktionieren auch `ssh host befehl`, `scp` und `rsync`, wenn gosh als Login-Shell gesetzt ist. Befehle lassen sich mit `;`, `&&` und `||` verketten und mit Pipes verbinden, z. B. `ssh host 'cd /srv && git log | head'`.
 
+### Startdateien
+
+Beim Start liest gosh Startdateien und führt sie wie ein Skript in der laufenden Shell aus (Variablen, die dort gesetzt werden, bleiben also erhalten):
+
+| Shell                         | Dateien (in dieser Reihenfolge)              | abschalten mit  |
+|-------------------------------|----------------------------------------------|-----------------|
+| Login-Shell                   | `/etc/gosh/profile`, `~/.gosh_profile`       | `--noprofile`   |
+| interaktive Shell             | `/etc/gosh/goshrc`, `~/.goshrc`              | `--norc`        |
+
+- Eine Login-Shell ist gosh mit `-l` oder wenn `argv[0]` mit `-` beginnt (so starten `login`, `sshd` und `su -` die Shell). Eine interaktive Login-Shell liest erst die Profil-, dann die `goshrc`-Dateien.
+- `gosh -c '…'` und Skripte lesen keine Startdateien, außer als Login-Shell (`gosh -l -c '…'`).
+- Fehlende Dateien werden übersprungen. Fehler werden mit Datei und Zeile gemeldet (`gosh: ~/.goshrc:4: foo: command not found`), die übrigen Zeilen laufen trotzdem.
+- Bash-Dateien wie `/etc/profile` oder `~/.bashrc` liest gosh bewusst nicht, weil es deren Syntax (`if`, Funktionen, …) nicht versteht.
+- Mit `source datei` (oder `. datei`) lässt sich eine Datei auch später einlesen, z. B. nach einer Änderung: `source ~/.goshrc`.
+
+Beispiel für `~/.goshrc`:
+
+```bash
+# Eigene Programme zuerst
+export PATH=$HOME/bin:$HOME/go/bin:$PATH
+export EDITOR=vim
+
+# Aliase
+alias ll='ls -l'
+alias ..='cd ..'
+
+# Prompt-Farben (Anführungszeichen wegen des ;)
+export GOSH_COLORS='user=1;38;5;208:path=38;5;205'
+
+# Weitere Einstellungen nur, wenn die Datei existiert
+test -f ~/.goshrc.local && source ~/.goshrc.local
+```
+
+Beispiel für `~/.gosh_profile` (wird nur von Login-Shells gelesen, z. B. beim Anmelden an der Konsole oder per `ssh host` ohne Befehl):
+
+```bash
+export LANG=de_DE.UTF-8
+export PATH=$HOME/bin:$PATH
+```
+
 ### Befehlslisten und Exit-Status
 
 Mehrere Befehle in einer Zeile werden wie in `sh` verknüpft:
@@ -83,6 +142,32 @@ Status 127
 
 Schlägt ein Programm fehl, gibt gosh selbst keine Meldung mehr aus (das Programm meldet den Fehler selbst), nur bei Fehlern von gosh, z. B. wenn ein Befehl nicht gefunden wird.
 
+### Wildcards
+
+Wörter mit `*`, `?` oder `[...]` werden durch die passenden Dateinamen ersetzt, sortiert:
+
+| Muster    | passt auf                                           |
+|-----------|-----------------------------------------------------|
+| `*`       | beliebig viele Zeichen (auch keine)                 |
+| `?`       | genau ein Zeichen                                   |
+| `[abc]`   | eines der Zeichen `a`, `b`, `c`                     |
+| `[a-z]`   | ein Zeichen aus dem Bereich                         |
+| `[!abc]`  | ein Zeichen außer `a`, `b`, `c` (auch `[^abc]`)     |
+
+```
+$ ls *.go
+main.go  main_test.go
+$ cat logs/2026-*/error.log
+$ ls -d */            # nur Verzeichnisse
+```
+
+- Muster gelten pro Pfadteil, `*` passt nie auf `/`: `*/*.go` findet `.go`-Dateien eine Ebene tiefer.
+- Versteckte Dateien (mit `.` am Anfang) werden nur gefunden, wenn das Muster selbst mit `.` beginnt: `*` findet `.bashrc` nicht, `.*rc` schon.
+- Passt keine Datei, bleibt das Wort unverändert stehen (wie in `sh`), `ls *.xyz` meldet dann also `ls` den Fehler.
+- In Anführungszeichen oder mit `\` davor sind die Zeichen normale Zeichen: `echo "*"`, `echo '*.go'`, `echo \*`.
+- Werte von Variablen werden nicht als Muster behandelt (anders als in `sh`): Nach `set P=*.go` gibt `echo $P` wörtlich `*.go` aus. So kann ein Variablenwert nie unbemerkt auf viele Dateien passen. `echo $DIR/*.go` funktioniert dagegen, weil das `*` direkt in der Zeile steht.
+- Bei einer Umleitung muss das Muster genau eine Datei treffen (`> *.log`), sonst meldet gosh `ambiguous redirect`.
+
 ### Pipes und Umleitungen
 
 ```
@@ -108,7 +193,71 @@ $ grep -c error < build.log
 - Operatoren in Anführungszeichen oder mit `\` davor sind normale Zeichen: `echo "a|b" 'c>d' e\>f`.
 - Der Exit-Status einer Pipeline ist der des letzten Befehls. Beendet sich ein Befehl am Ende (z. B. `head`), bekommt der schreibende Befehl davor `SIGPIPE`, `yes | head -1` endet also sofort.
 - Die Built-ins `pwd` und `help` lassen sich umleiten und in Pipes verwenden (`help | less`). `cd`, `set`, `export`, `exit` und `quit` verändern die Shell selbst und sind in einer Pipeline nicht erlaubt.
-- Ein einzelnes `&` (Hintergrundprozesse) gibt es noch nicht, es wird als normales Zeichen übergeben.
+
+### Aliase
+
+Ein Alias ist ein Kurzname für einen Befehl, am besten in `~/.goshrc` definiert:
+
+```bash
+alias ll='ls -l'
+alias la='ls -la'
+alias ..='cd ..'
+alias gs='git status'
+alias ls='ls --color=auto'      # ein Alias darf den eigenen Namen enthalten
+alias please='sudo '            # endet mit Leerzeichen: das nächste Wort wird auch ersetzt
+```
+
+| Befehl                  | Bedeutung                                         |
+|-------------------------|---------------------------------------------------|
+| `alias name='wert'`     | definiert einen Alias (mehrere in einem Aufruf möglich) |
+| `alias`                 | listet alle Aliase (in einer Form, die sich wieder einlesen lässt) |
+| `alias name`            | zeigt einen Alias                                 |
+| `unalias name`          | entfernt einen Alias, `unalias -a` alle           |
+
+- Ersetzt wird nur das erste Wort eines Befehls, also am Zeilenanfang und nach `;`, `&&`, `||`, `|` und `&`: `ll | less` funktioniert, `echo ll` gibt `ll` aus.
+- Der Wert darf selbst mehrere Befehle enthalten (`alias up='cd .. && ls'`) und wird wiederum auf Aliase geprüft. Ein Alias, der gerade ersetzt wird, wird darin nicht noch einmal ersetzt, deshalb funktioniert `alias ls='ls --color=auto'`.
+- Endet der Wert mit einem Leerzeichen, wird auch das nächste Wort als Alias geprüft: Mit den Aliasen oben wird `please ll` zu `sudo ls --color=auto -l`.
+- Mit `\ll` oder `'ll'` umgeht man den Alias und ruft das Programm direkt auf.
+- Aliase gelten nur in interaktiven Shells (wie in bash), also auch in `~/.goshrc`, aber nicht in Skripten und bei `gosh -c`. Ein Alias wirkt erst ab der nächsten Zeile, nicht in der Zeile, in der er definiert wird.
+- Erlaubt sind Namen aus Buchstaben, Ziffern und `_ - . + : , @ % ^`.
+- Aliase werden auch mit Tab vervollständigt.
+
+### Job-Control
+
+In einer interaktiven Shell läuft jede Befehlszeile (bzw. jede Pipeline) als eigener *Job* in einer eigenen Prozessgruppe:
+
+```
+$ sleep 100 &                 # im Hintergrund starten
+[1] 12345
+$ vim notizen.txt             # Ctrl+Z hält vim an
+^Z
+[2]+  Stopped                 vim notizen.txt
+$ jobs
+[1]-  Running                 sleep 100 &
+[2]+  Stopped                 vim notizen.txt
+$ fg                          # vim wieder im Vordergrund
+$ bg %2                       # oder: angehaltenen Job im Hintergrund weiterlaufen lassen
+```
+
+| Befehl / Taste | Bedeutung                                                                 |
+|----------------|---------------------------------------------------------------------------|
+| `befehl &`     | startet den Befehl im Hintergrund, gosh wartet nicht auf ihn (`$?` ist 0) |
+| Ctrl+Z         | hält den Vordergrund-Job an (`$?` wird 128+SIGTSTP, unter Linux 148)      |
+| Ctrl+C         | bricht nur den Vordergrund-Job ab, nicht die Shell                        |
+| `jobs`         | listet laufende und angehaltene Jobs                                      |
+| `fg [%n]`      | holt Job `n` in den Vordergrund (und setzt ihn fort, falls angehalten)    |
+| `bg [%n]`      | setzt einen angehaltenen Job im Hintergrund fort                          |
+| `wait [%n]`    | wartet auf Job `n` bzw. auf alle Hintergrund-Jobs                         |
+
+- Ohne Angabe gilt der *aktuelle* Job (in `jobs` mit `+` markiert, der zuletzt angehaltene oder in den Hintergrund geschickte), `%-` ist der vorherige (`-`). `%n` und `n` meinen Job Nummer `n`.
+- Beendete Hintergrund-Jobs meldet gosh vor dem nächsten Prompt (`[1]+  Done   sleep 100`, bei Fehlern `Exit N`).
+- Liest ein Hintergrund-Job vom Terminal, wird er angehalten (wie in bash), mit `fg` bekommt er die Eingabe.
+- Die Terminal-Einstellungen werden gesichert und wiederhergestellt: Nach dem Anhalten von `vim` oder `less` funktioniert der Prompt normal, nach `fg` bekommt das Programm seine Einstellungen zurück.
+- `exit` (oder Ctrl+D) mit angehaltenen Jobs warnt einmal (`there are stopped jobs`), ein zweites `exit` direkt danach beendet gosh.
+- `cd`, `set`, `export`, `exit`, `source`, `fg`, `bg` und `wait` lassen sich nicht mit `&` im Hintergrund starten.
+- In Skripten und mit `gosh -c` gibt es keine Job-Control (kein Ctrl+Z, kein `fg`/`bg`), `&` und `wait` funktionieren aber. Hintergrund-Jobs lesen dort von `/dev/null`.
+- Wird ein angehaltener Job von außen fortgesetzt (`kill -CONT`), zeigt `jobs` ihn weiter als `Stopped`, bis er endet oder erneut angehalten wird; `fg` und `bg` funktionieren trotzdem.
+- Einen Job beenden lässt sich mit `kill` über die Prozess-ID (z. B. `kill 12345`); `kill %1` versteht gosh noch nicht.
 
 ### Farben
 

alias.go

@@ -0,0 +1,191 @@
+package main
+
+// Aliases: like in bash, an alias replaces the first word of a command and
+// is only expanded in interactive shells (including the startup files), not
+// in scripts or with gosh -c.
+
+import (
+	"fmt"
+	"io"
+	"sort"
+	"strings"
+	"sync"
+)
+
+var (
+	aliasMu sync.Mutex
+	aliases = map[string]string{}
+)
+
+// isAliasName reports whether s can be an alias name: letters, digits and a
+// few punctuation characters, but nothing that is special to the shell.
+func isAliasName(s string) bool {
+	if s == "" {
+		return false
+	}
+	for _, r := range s {
+		switch {
+		case r >= 'a' && r <= 'z', r >= 'A' && r <= 'Z', r >= '0' && r <= '9':
+		case strings.ContainsRune("_-.+:,@%^", r):
+		default:
+			return false
+		}
+	}
+	return true
+}
+
+// lookupAlias returns the value of an alias.
+func lookupAlias(name string) (string, bool) {
+	aliasMu.Lock()
+	defer aliasMu.Unlock()
+	value, ok := aliases[name]
+	return value, ok
+}
+
+// aliasNames returns the names of all aliases, sorted.
+func aliasNames() []string {
+	aliasMu.Lock()
+	defer aliasMu.Unlock()
+	names := make([]string, 0, len(aliases))
+	for name := range aliases {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+// expandAliases replaces aliases at the start of every command in line (at
+// the start and after ;, &, &&, || and |). The value of an alias is expanded
+// again, except for aliases that are already being expanded, so that e.g.
+// alias ls='ls --color' works. If the value ends with a blank, the next word
+// is checked for an alias too. Quoted or escaped words (\ls, 'ls') are never
+// replaced.
+func expandAliases(line string) string {
+	return expandAliasesIn(line, map[string]bool{})
+}
+
+func expandAliasesIn(line string, active map[string]bool) string {
+	var (
+		out        strings.Builder
+		quote      byte
+		escaped    bool
+		commandPos = true // the next word is the name of a command
+	)
+
+	for i := 0; i < len(line); i++ {
+		ch := line[i]
+		if quote == 0 && !escaped && commandPos {
+			if ch == ' ' || ch == '\t' {
+				out.WriteByte(ch)
+				continue
+			}
+			commandPos = false
+			end := i
+			for end < len(line) && strings.IndexByte(" \t\n;&|<>", line[end]) < 0 {
+				end++
+			}
+			name := line[i:end]
+			if value, ok := lookupAlias(name); ok && isAliasName(name) && !active[name] {
+				active[name] = true
+				out.WriteString(expandAliasesIn(value, active))
+				delete(active, name)
+				// A trailing blank makes the next word a command name too
+				commandPos = strings.HasSuffix(value, " ") || strings.HasSuffix(value, "\t")
+				i = end - 1
+				continue
+			}
+		}
+
+		out.WriteByte(ch)
+		switch {
+		case escaped:
+			escaped = false
+		case quote == '\'':
+			if ch == '\'' {
+				quote = 0
+			}
+		case ch == '\\':
+			escaped = true
+		case quote == '"':
+			if ch == '"' {
+				quote = 0
+			}
+		case ch == '"' || ch == '\'':
+			quote = ch
+		case ch == '#' && (i == 0 || strings.IndexByte(" \t", line[i-1]) >= 0):
+			// Comment until the end of the line
+			out.WriteString(line[i+1:])
+			return out.String()
+		case ch == ';' || ch == '|':
+			commandPos = true
+		case ch == '&':
+			// & and && separate commands, &>, >& and <& do not
+			if !(i+1 < len(line) && line[i+1] == '>') && !(i > 0 && strings.IndexByte("<>", line[i-1]) >= 0) {
+				commandPos = true
+			}
+		}
+	}
+	return out.String()
+}
+
+// quoteAlias quotes a value for the output of alias, so that it can be read
+// back: 'value' with ' written as '\”.
+func quoteAlias(value string) string {
+	return "'" + strings.ReplaceAll(value, "'", `'\''`) + "'"
+}
+
+// builtinAlias defines aliases (alias name=value ...), prints them (alias
+// name ...) or lists all of them (alias).
+func builtinAlias(args []string, stdout io.Writer) error {
+	if len(args) == 1 {
+		for _, name := range aliasNames() {
+			value, _ := lookupAlias(name)
+			fmt.Fprintf(stdout, "alias %s=%s\n", name, sanitize(quoteAlias(value)))
+		}
+		return nil
+	}
+
+	var err error
+	for _, arg := range args[1:] {
+		name, value, define := strings.Cut(arg, "=")
+		if !isAliasName(name) {
+			err = fmt.Errorf("alias: `%s': invalid alias name", sanitize(name))
+			continue
+		}
+		if define {
+			aliasMu.Lock()
+			aliases[name] = value
+			aliasMu.Unlock()
+			continue
+		}
+		if value, ok := lookupAlias(name); ok {
+			fmt.Fprintf(stdout, "alias %s=%s\n", name, sanitize(quoteAlias(value)))
+		} else {
+			err = fmt.Errorf("alias: %s: not found", sanitize(name))
+		}
+	}
+	return err
+}
+
+// builtinUnalias removes aliases (unalias name ...) or all of them
+// (unalias -a).
+func builtinUnalias(args []string) error {
+	if len(args) < 2 {
+		return fmt.Errorf("usage: unalias [-a] name ...")
+	}
+	aliasMu.Lock()
+	defer aliasMu.Unlock()
+	if args[1] == "-a" {
+		aliases = map[string]string{}
+		return nil
+	}
+	var err error
+	for _, name := range args[1:] {
+		if _, ok := aliases[name]; !ok {
+			err = fmt.Errorf("unalias: %s: not found", sanitize(name))
+			continue
+		}
+		delete(aliases, name)
+	}
+	return err
+}

alias_test.go

@@ -0,0 +1,164 @@
+package main
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// withAliases sets the aliases for a test and restores them afterwards.
+func withAliases(t *testing.T, defs map[string]string) {
+	t.Helper()
+	aliasMu.Lock()
+	saved := aliases
+	aliases = map[string]string{}
+	for name, value := range defs {
+		aliases[name] = value
+	}
+	aliasMu.Unlock()
+	t.Cleanup(func() {
+		aliasMu.Lock()
+		aliases = saved
+		aliasMu.Unlock()
+	})
+}
+
+func TestExpandAliases(t *testing.T) {
+	withAliases(t, map[string]string{
+		"ll":    "ls -l",
+		"ls":    "ls --color",
+		"..":    "cd ..",
+		"e":     "echo ",
+		"w":     "world",
+		"a":     "b",
+		"b":     "a",
+		"multi": "cd /tmp && ls",
+	})
+
+	tests := []struct {
+		input, want string
+	}{
+		{"ll", "ls --color -l"},
+		{"  ll -a", "  ls --color -l -a"},
+		{"ls", "ls --color"},
+		{"..", "cd .."},
+		// Only the command name is replaced
+		{"echo ll", "echo ll"},
+		{"ll ll", "ls --color -l ll"},
+		// ... also after ;, &&, ||, | and &
+		{"ll; ll && ll || ll | ll & ll", "ls --color -l; ls --color -l && ls --color -l || ls --color -l | ls --color -l & ls --color -l"},
+		// but not after redirections with &
+		{"ll 2>&1 ll", "ls --color -l 2>&1 ll"},
+		{"ll &> ll", "ls --color -l &> ll"},
+		// Quoted or escaped words are not replaced
+		{`\ll`, `\ll`},
+		{`'ll'`, `'ll'`},
+		{`"ll"`, `"ll"`},
+		{`echo "a; ll"`, `echo "a; ll"`},
+		{`echo 'a | ll'`, `echo 'a | ll'`},
+		// A trailing blank makes the next word a command name too
+		{"e w", "echo  world"},
+		{"e e w", "echo  echo  world"},
+		// Recursion stops at aliases that are already being expanded
+		{"a", "a"},
+		{"b", "b"},
+		// The value can contain several commands
+		{"multi", "cd /tmp && ls --color"},
+		// Comments are left alone
+		{"echo x # ll", "echo x # ll"},
+	}
+	for _, tc := range tests {
+		if got := expandAliases(tc.input); got != tc.want {
+			t.Errorf("expandAliases(%q) = %q, want %q", tc.input, got, tc.want)
+		}
+	}
+}
+
+func TestBuiltinAlias(t *testing.T) {
+	withAliases(t, nil)
+
+	run := func(args ...string) (string, error) {
+		var out bytes.Buffer
+		err := builtinAlias(append([]string{"alias"}, args...), &out)
+		return out.String(), err
+	}
+
+	if _, err := run("ll=ls -l", "q=echo it's", "..=cd .."); err != nil {
+		t.Fatal(err)
+	}
+	out, _ := run()
+	want := "alias ..='cd ..'\nalias ll='ls -l'\nalias q='echo it'\\''s'\n"
+	if out != want {
+		t.Errorf("alias = %q, want %q", out, want)
+	}
+	if out, _ := run("ll"); out != "alias ll='ls -l'\n" {
+		t.Errorf("alias ll = %q", out)
+	}
+	if _, err := run("nope"); err == nil || err.Error() != "alias: nope: not found" {
+		t.Errorf("alias nope: %v", err)
+	}
+	for _, name := range []string{"a/b", "a=b", "$x", "a b", ""} {
+		if isAliasName(name) {
+			t.Errorf("isAliasName(%q) = true", name)
+		}
+	}
+	if _, err := run("a/b=x"); err == nil || !strings.Contains(err.Error(), "invalid alias name") {
+		t.Errorf("alias a/b=x: %v", err)
+	}
+
+	if err := builtinUnalias([]string{"unalias", "ll", "nope"}); err == nil || err.Error() != "unalias: nope: not found" {
+		t.Errorf("unalias nope: %v", err)
+	}
+	if _, ok := lookupAlias("ll"); ok {
+		t.Error("ll still defined after unalias")
+	}
+	builtinUnalias([]string{"unalias", "-a"})
+	if names := aliasNames(); len(names) != 0 {
+		t.Errorf("aliases after unalias -a: %q", names)
+	}
+}
+
+func TestExecInput_Aliases(t *testing.T) {
+	withAliases(t, nil)
+	origDir, _ := os.Getwd()
+	defer os.Chdir(origDir)
+	dir := t.TempDir()
+	os.Chdir(dir)
+	defer func(saved bool) { interactiveShell = saved }(interactiveShell)
+
+	// Aliases are expanded in interactive shells only
+	interactiveShell = true
+	execInput(`alias say='echo hello' to=out`)
+	execInput("say world > out")
+	if got, _ := os.ReadFile("out"); string(got) != "hello world\n" {
+		t.Errorf("alias in interactive shell: out = %q", got)
+	}
+
+	interactiveShell = false
+	os.Remove("out")
+	if err := execInput("say world > out"); err == nil {
+		t.Error("alias was expanded in a non-interactive shell")
+	}
+
+	// alias works in pipelines (listing), unalias does not
+	interactiveShell = true
+	execInput("alias | grep say > out")
+	if got, _ := os.ReadFile(filepath.Join(dir, "out")); string(got) != "alias say='echo hello'\n" {
+		t.Errorf("alias | grep = %q", got)
+	}
+	if err := execInput("echo | unalias say"); err == nil {
+		t.Error("unalias in a pipeline must fail")
+	}
+}
+
+func TestShellCompleter_Aliases(t *testing.T) {
+	withAliases(t, map[string]string{"gst": "git status"})
+	t.Setenv("PATH", t.TempDir())
+	got, length := completeLine("gs")
+	if !reflect.DeepEqual(got, []string{"t "}) || length != 2 {
+		t.Errorf("completion of gs = %q, %d", got, length)
+	}
+}

go.mod

@@ -7,4 +7,4 @@ require (
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 )
 
-require golang.org/x/sys v0.48.0 // indirect
+require golang.org/x/sys v0.48.0

jobs.go

@@ -0,0 +1,536 @@
+package main
+
+// Job control: in an interactive shell every pipeline runs in its own process
+// group, which gets the terminal while it runs in the foreground. Ctrl+Z stops
+// the foreground job, "&" starts a job in the background, and the builtins
+// jobs, fg, bg and wait manage the jobs. Without a terminal (scripts, gosh -c)
+// there is no job control, but "&" and wait still work.
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"os/signal"
+	"strconv"
+	"strings"
+	"syscall"
+
+	"github.com/chzyer/readline"
+	"golang.org/x/sys/unix"
+)
+
+// proc is a stage of a job: a process, or a builtin or a stage that failed to
+// start (both without process).
+type proc struct {
+	cmd      *exec.Cmd  // nil if the stage is no process
+	done     chan error // the result of a stage without process
+	finished bool
+	stopped  bool
+	err      error
+}
+
+// job is a pipeline that was started by the shell.
+type job struct {
+	id    int    // number in the job table, 0 if not in the table
+	pgid  int    // process group, 0 without job control or processes
+	text  string // the command line
+	procs []*proc
+	tty   *readline.State // terminal modes of the job when it was stopped
+}
+
+var (
+	jobControl       bool            // job control is enabled
+	interactiveShell bool            // the shell reads commands from a user
+	ttyFd            int             // the terminal of the shell
+	shellPgid        int             // the process group of the shell
+	origPgid         int             // the foreground process group at start
+	shellTTY         *readline.State // terminal modes of the shell
+	jobTable         []*job          // background and stopped jobs
+	exitWarned       bool            // "there are stopped jobs" was shown
+)
+
+// initJobControl enables job control if stdin is a terminal: the shell moves
+// into its own process group and takes the terminal.
+func initJobControl() {
+	fd := int(os.Stdin.Fd())
+	if !readline.IsTerminal(fd) {
+		return
+	}
+	pgrp, err := unix.IoctlGetInt(fd, unix.TIOCGPGRP)
+	if err != nil {
+		return
+	}
+	pid := os.Getpid()
+	if syscall.Getpgrp() != pid {
+		if err := syscall.Setpgid(0, 0); err != nil {
+			return
+		}
+	}
+	origPgid, ttyFd, shellPgid = pgrp, fd, pid
+	if err := setForeground(pid); err != nil {
+		return
+	}
+	// Ctrl+Z must not stop the shell itself. (signal.Ignore would be
+	// inherited by the child processes.)
+	signal.Notify(make(chan os.Signal, 1), syscall.SIGTSTP)
+	jobControl = true
+}
+
+// releaseTerminal gives the terminal back to the process group that had it
+// when the shell started.
+func releaseTerminal() {
+	if jobControl && origPgid > 0 && origPgid != shellPgid {
+		setForeground(origPgid)
+	}
+}
+
+// setForeground makes pgid the foreground process group of the terminal.
+func setForeground(pgid int) error {
+	// The shell gets SIGTTOU if it does this while it is in the background
+	// (when it takes the terminal back from a job), unless the signal is
+	// ignored. It is only ignored for this call, since ignored signals are
+	// inherited by child processes.
+	signal.Ignore(syscall.SIGTTOU)
+	defer signal.Reset(syscall.SIGTTOU)
+	return unix.IoctlSetPointerInt(ttyFd, unix.TIOCSPGRP, pgid)
+}
+
+// ttyIndex returns the index of the file in fds that is the terminal of the
+// shell, or -1.
+func ttyIndex(fds [3]*os.File) int {
+	tty, err := os.Stdin.Stat()
+	if err != nil {
+		return -1
+	}
+	for i, f := range fds {
+		if info, err := f.Stat(); err == nil && os.SameFile(info, tty) {
+			return i
+		}
+	}
+	return -1
+}
+
+// finishedProc returns a proc without process that already has its result.
+func finishedProc(err error) *proc {
+	p := &proc{done: make(chan error, 1)}
+	p.done <- err
+	return p
+}
+
+// running reports whether a process of the job is running.
+func (j *job) running() bool {
+	for _, p := range j.procs {
+		if p.cmd != nil && !p.finished && !p.stopped {
+			return true
+		}
+	}
+	return false
+}
+
+// stopped reports whether the job is stopped: no process is running, but
+// one is stopped.
+func (j *job) stopped() bool {
+	if j.running() {
+		return false
+	}
+	for _, p := range j.procs {
+		if p.stopped {
+			return true
+		}
+	}
+	return false
+}
+
+// finished reports whether all stages of the job have finished.
+func (j *job) finished() bool {
+	for _, p := range j.procs {
+		if !p.finished {
+			return false
+		}
+	}
+	return true
+}
+
+// update records a status change of process pid.
+func (j *job) update(pid int, ws syscall.WaitStatus) {
+	for _, p := range j.procs {
+		if p.cmd == nil || p.cmd.Process.Pid != pid {
+			continue
+		}
+		switch {
+		case ws.Stopped():
+			p.stopped = true
+		case ws.Exited() || ws.Signaled():
+			p.finished, p.stopped = true, false
+			p.err = waitStatusError(ws)
+			p.cmd.Process.Release()
+		}
+	}
+}
+
+// waitStatusError converts the status of a finished process into an error:
+// nil for exit code 0, otherwise a statusError with the exit code, or 128+n
+// if the process was killed by signal n.
+func waitStatusError(ws syscall.WaitStatus) error {
+	switch {
+	case ws.Signaled():
+		return statusError(128 + int(ws.Signal()))
+	case ws.ExitStatus() != 0:
+		return statusError(ws.ExitStatus())
+	}
+	return nil
+}
+
+// waitFlags returns the options for wait4: WUNTRACED to see stopped
+// processes (with job control) and WNOHANG to not block.
+//
+// WCONTINUED is not used: Go's syscall.WaitStatus decodes the "continued"
+// status wrongly on FreeBSD (as killed by SIGCONT) and macOS (as stopped).
+// The shell marks jobs as running itself when it continues them (fg, bg); a
+// job continued from outside (kill -CONT) stays "Stopped" in the job table
+// until it stops again or exits.
+func waitFlags(j *job, nohang bool) int {
+	flags := 0
+	if jobControl && j.pgid != 0 {
+		flags |= syscall.WUNTRACED
+	}
+	if nohang {
+		flags |= syscall.WNOHANG
+	}
+	return flags
+}
+
+// wait waits until no process of the job is running any more (all finished
+// or, with job control, stopped). With nohang it only collects the status
+// changes that are already available and does not block.
+func (j *job) wait(nohang bool) {
+	flags := waitFlags(j, nohang)
+
+	for {
+		// With job control all processes of the job are in its process
+		// group, otherwise they are waited for one by one.
+		target := 0
+		if jobControl && j.pgid != 0 {
+			if !j.running() && !(nohang && j.stopped()) {
+				break
+			}
+			target = -j.pgid
+		} else {
+			if nohang {
+				// Check every process once
+				for _, p := range j.procs {
+					if p.cmd == nil || p.finished {
+						continue
+					}
+					var ws syscall.WaitStatus
+					if pid, err := syscall.Wait4(p.cmd.Process.Pid, &ws, flags, nil); err == nil && pid > 0 {
+						j.update(pid, ws)
+					}
+				}
+				break
+			}
+			for _, p := range j.procs {
+				if p.cmd != nil && !p.finished {
+					target = p.cmd.Process.Pid
+					break
+				}
+			}
+			if target == 0 {
+				break
+			}
+		}
+
+		var ws syscall.WaitStatus
+		pid, err := syscall.Wait4(target, &ws, flags, nil)
+		if errors.Is(err, syscall.EINTR) {
+			continue
+		}
+		if err != nil {
+			// Should not happen; do not wait forever
+			for _, p := range j.procs {
+				if p.cmd != nil && !p.finished {
+					p.finished, p.stopped = true, false
+				}
+			}
+			break
+		}
+		if pid == 0 {
+			break // nohang and nothing changed
+		}
+		j.update(pid, ws)
+	}
+
+	// Stages without process (builtins in pipelines)
+	for _, p := range j.procs {
+		if p.cmd != nil || p.finished {
+			continue
+		}
+		if nohang || j.stopped() {
+			select {
+			case p.err = <-p.done:
+				p.finished = true
+			default:
+			}
+		} else {
+			p.err = <-p.done
+			p.finished = true
+		}
+	}
+}
+
+// result returns the error of the last stage of a finished job (so $? is its
+// exit status, like in sh) and prints the errors of the other stages.
+func (j *job) result() error {
+	for _, p := range j.procs[:len(j.procs)-1] {
+		printError(p.err)
+	}
+	return j.procs[len(j.procs)-1].err
+}
+
+// waitForeground waits for a job in the foreground. If it is stopped, it is
+// added to the job table.
+func waitForeground(j *job) error {
+	j.wait(false)
+	if jobControl && j.pgid != 0 {
+		setForeground(shellPgid)
+		if j.stopped() {
+			j.tty, _ = readline.GetState(ttyFd)
+		}
+		if shellTTY != nil {
+			readline.Restore(ttyFd, shellTTY)
+		}
+	}
+
+	if j.stopped() {
+		addJob(j)
+		fmt.Fprintln(os.Stderr)
+		fmt.Fprintln(os.Stderr, j.describe("Stopped"))
+		return statusError(128 + int(syscall.SIGTSTP))
+	}
+	removeJob(j)
+	j.wait(false) // wait for the builtins, if any
+	return j.result()
+}
+
+// addJob adds j to the job table (if it is not there yet) and makes it the
+// current job.
+func addJob(j *job) {
+	removeJob(j)
+	if j.id == 0 {
+		for _, other := range jobTable {
+			j.id = max(j.id, other.id)
+		}
+		j.id++
+	}
+	jobTable = append(jobTable, j)
+}
+
+// removeJob removes j from the job table.
+func removeJob(j *job) {
+	for i, other := range jobTable {
+		if other == j {
+			jobTable = append(jobTable[:i], jobTable[i+1:]...)
+			return
+		}
+	}
+}
+
+// describe formats a job for jobs and the notifications, like bash:
+// "[1]+  Stopped                 sleep 30". The current job (the last one in
+// the table, i.e. the one stopped or put into the background most recently) is
+// marked with +, the previous one with -.
+func (j *job) describe(state string) string {
+	mark := ' '
+	if n := len(jobTable); n > 0 && jobTable[n-1] == j {
+		mark = '+'
+	} else if n > 1 && jobTable[n-2] == j {
+		mark = '-'
+	}
+	text := j.text
+	if state == "Running" {
+		text += " &"
+	}
+	return fmt.Sprintf("[%d]%c  %-24s%s", j.id, mark, state, sanitize(text))
+}
+
+// state returns the state of a job for jobs and the notifications.
+func (j *job) state() string {
+	switch {
+	case j.stopped():
+		return "Stopped"
+	case !j.finished():
+		return "Running"
+	}
+	if status := exitStatus(j.procs[len(j.procs)-1].err); status != 0 {
+		return "Exit " + strconv.Itoa(status)
+	}
+	return "Done"
+}
+
+// hasStoppedJobs reports whether a job in the table is stopped.
+func hasStoppedJobs() bool {
+	for _, j := range jobTable {
+		if j.stopped() {
+			return true
+		}
+	}
+	return false
+}
+
+// reapJobs collects the status changes of the background jobs, reports
+// finished and newly stopped jobs (if notify is set) and removes finished
+// jobs from the table.
+func reapJobs(notify bool) {
+	for _, j := range append([]*job(nil), jobTable...) {
+		wasStopped := j.stopped()
+		j.wait(true)
+		switch {
+		case j.finished():
+			if notify {
+				for _, p := range j.procs {
+					printError(p.err)
+				}
+				fmt.Fprintln(os.Stderr, j.describe(j.state()))
+			}
+			removeJob(j)
+		case j.stopped() && !wasStopped:
+			addJob(j) // the current job now
+			if notify {
+				fmt.Fprintln(os.Stderr, j.describe("Stopped"))
+			}
+		}
+	}
+}
+
+// findJob returns the job for a job spec: %N or N for job N, %+, %% or nothing
+// for the current job, %- for the previous one.
+func findJob(cmd string, args []string) (*job, error) {
+	spec := "%+"
+	if len(args) > 1 {
+		spec = args[1]
+	}
+	n := len(jobTable)
+	switch spec {
+	case "%+", "%%", "%":
+		if n > 0 {
+			return jobTable[n-1], nil
+		}
+		return nil, fmt.Errorf("%s: current: no such job", cmd)
+	case "%-":
+		if n > 1 {
+			return jobTable[n-2], nil
+		}
+		return nil, fmt.Errorf("%s: previous: no such job", cmd)
+	}
+	id, err := strconv.Atoi(strings.TrimPrefix(spec, "%"))
+	if err == nil {
+		for _, j := range jobTable {
+			if j.id == id {
+				return j, nil
+			}
+		}
+	}
+	return nil, fmt.Errorf("%s: %s: no such job", cmd, sanitize(spec))
+}
+
+// continueJob sends SIGCONT to a stopped job.
+func continueJob(j *job) {
+	for _, p := range j.procs {
+		p.stopped = false
+	}
+	if j.pgid != 0 {
+		syscall.Kill(-j.pgid, syscall.SIGCONT)
+	}
+}
+
+// builtinJobs lists the jobs.
+func builtinJobs(stdout io.Writer) error {
+	for _, j := range jobTable {
+		j.wait(true)
+	}
+	for _, j := range append([]*job(nil), jobTable...) {
+		fmt.Fprintln(stdout, j.describe(j.state()))
+		if j.finished() {
+			removeJob(j)
+		}
+	}
+	return nil
+}
+
+// builtinFg continues a job in the foreground and waits for it.
+func builtinFg(args []string, stdout io.Writer) error {
+	if !jobControl {
+		return errors.New("fg: no job control")
+	}
+	j, err := findJob("fg", args)
+	if err != nil {
+		return err
+	}
+	fmt.Fprintln(stdout, sanitize(j.text))
+
+	if j.pgid != 0 {
+		shellTTY, _ = readline.GetState(ttyFd)
+		if j.stopped() && j.tty != nil {
+			readline.Restore(ttyFd, j.tty)
+		}
+		setForeground(j.pgid)
+	}
+	continueJob(j)
+	return waitForeground(j)
+}
+
+// builtinBg continues a stopped job in the background.
+func builtinBg(args []string, stdout io.Writer) error {
+	if !jobControl {
+		return errors.New("bg: no job control")
+	}
+	j, err := findJob("bg", args)
+	if err != nil {
+		return err
+	}
+	if !j.stopped() {
+		return fmt.Errorf("bg: job %d already in background", j.id)
+	}
+	continueJob(j)
+	addJob(j) // the current job now
+	fmt.Fprintln(stdout, j.describe("Running"))
+	return nil
+}
+
+// builtinWait waits for a job, or for all background jobs. Stopped jobs are
+// not waited for.
+func builtinWait(args []string) error {
+	jobs := append([]*job(nil), jobTable...)
+	if len(args) > 1 {
+		j, err := findJob("wait", args)
+		if err != nil {
+			return err
+		}
+		jobs = []*job{j}
+	}
+
+	var err error
+	for _, j := range jobs {
+		j.wait(false)
+		err = nil
+		if j.finished() {
+			removeJob(j)
+			err = j.result()
+		}
+	}
+	return err
+}
+
+// exitShell exits the shell, unless there are stopped jobs and the user was
+// not warned yet (like bash).
+func exitShell(code int) error {
+	if interactiveShell && hasStoppedJobs() && !exitWarned {
+		exitWarned = true
+		return errors.New("there are stopped jobs")
+	}
+	releaseTerminal()
+	os.Exit(code)
+	return nil
+}

jobs_linux_test.go

@@ -0,0 +1,204 @@
+package main
+
+import (
+	"bytes"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+// openPty opens a new pseudo terminal and returns the master and slave side.
+func openPty(t *testing.T) (*os.File, *os.File) {
+	t.Helper()
+	master, err := os.OpenFile("/dev/ptmx", os.O_RDWR, 0)
+	if err != nil {
+		t.Skipf("no pty available: %v", err)
+	}
+	if err := unix.IoctlSetPointerInt(int(master.Fd()), unix.TIOCSPTLCK, 0); err != nil {
+		t.Fatal(err)
+	}
+	n, err := unix.IoctlGetInt(int(master.Fd()), unix.TIOCGPTN)
+	if err != nil {
+		t.Fatal(err)
+	}
+	slave, err := os.OpenFile("/dev/pts/"+strconv.Itoa(n), os.O_RDWR|syscall.O_NOCTTY, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return master, slave
+}
+
+// ptyShell is the shell running on a pseudo terminal.
+type ptyShell struct {
+	t      *testing.T
+	master *os.File
+	mu     sync.Mutex
+	out    bytes.Buffer
+	cmd    *exec.Cmd
+}
+
+func startPtyShell(t *testing.T) *ptyShell {
+	bin := buildShell(t)
+	master, slave := openPty(t)
+	cmd := exec.Command(bin, "--norc")
+	cmd.Stdin, cmd.Stdout, cmd.Stderr = slave, slave, slave
+	cmd.Env = append(os.Environ(), "NO_COLOR=1")
+	// New session with the pty as controlling terminal, like a terminal
+	// emulator does
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true, Setctty: true, Ctty: 0}
+	if err := cmd.Start(); err != nil {
+		t.Fatal(err)
+	}
+	slave.Close()
+
+	s := &ptyShell{t: t, master: master, cmd: cmd}
+	go func() {
+		buf := make([]byte, 4096)
+		for {
+			n, err := master.Read(buf)
+			s.mu.Lock()
+			s.out.Write(buf[:n])
+			s.mu.Unlock()
+			if err != nil {
+				return
+			}
+		}
+	}()
+	t.Cleanup(func() {
+		cmd.Process.Kill()
+		cmd.Wait()
+		master.Close()
+	})
+	s.expect("$ ")
+	return s
+}
+
+func (s *ptyShell) send(text string) {
+	s.master.WriteString(text)
+}
+
+// expect waits until want appears in the output after the position of the
+// last match and consumes the output up to it.
+func (s *ptyShell) expect(want string) {
+	s.t.Helper()
+	deadline := time.Now().Add(5 * time.Second)
+	for time.Now().Before(deadline) {
+		s.mu.Lock()
+		out := s.out.String()
+		if i := strings.Index(out, want); i >= 0 {
+			s.out.Next(i + len(want))
+			s.mu.Unlock()
+			return
+		}
+		s.mu.Unlock()
+		time.Sleep(20 * time.Millisecond)
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.t.Fatalf("timeout waiting for %q, output:\n%s", want, s.out.String())
+}
+
+func TestWaitFlags_NoWCONTINUED(t *testing.T) {
+	defer func(saved bool) { jobControl = saved }(jobControl)
+	jobControl = true
+	j := &job{pgid: 1}
+	for _, nohang := range []bool{false, true} {
+		flags := waitFlags(j, nohang)
+		if flags&syscall.WCONTINUED != 0 {
+			t.Errorf("waitFlags(nohang=%v) contains WCONTINUED, which Go decodes wrongly on BSD", nohang)
+		}
+		if flags&syscall.WUNTRACED == 0 {
+			t.Errorf("waitFlags(nohang=%v) misses WUNTRACED", nohang)
+		}
+	}
+}
+
+func TestJobControl(t *testing.T) {
+	s := startPtyShell(t)
+
+	// Ctrl+Z stops the foreground job, the shell gets the terminal back
+	s.send("sleep 30\n")
+	time.Sleep(300 * time.Millisecond)
+	s.send("\x1a")
+	s.expect("[1]+  Stopped                 sleep 30")
+	s.send("jobs\n")
+	s.expect("[1]+  Stopped                 sleep 30")
+
+	// bg continues it in the background
+	s.send("bg\n")
+	s.expect("[1]+  Running                 sleep 30 &")
+
+	// After bg the job keeps running and is not reported as finished
+	// (regression: on FreeBSD the "continued" status was read as killed by
+	// SIGCONT, "Exit 147")
+	time.Sleep(300 * time.Millisecond)
+	s.send("jobs\n")
+	s.expect("[1]+  Running                 sleep 30 &")
+
+	// fg brings it back, Ctrl+C reaches only the job
+	s.send("fg %1\n")
+	s.expect("sleep 30")
+	time.Sleep(300 * time.Millisecond)
+	s.send("\x03")
+	s.send("echo status=$?\n")
+	s.expect("status=130")
+
+	// A pipeline is stopped and continued as a whole
+	s.send("sleep 30 | cat\n")
+	time.Sleep(300 * time.Millisecond)
+	s.send("\x1a")
+	s.expect("Stopped                 sleep 30 | cat")
+	s.send("fg\n")
+	time.Sleep(300 * time.Millisecond)
+	s.send("\x03")
+	s.send("echo pipeline=$?\n")
+	s.expect("pipeline=130")
+
+	// A background job that reads from the terminal is stopped (SIGTTIN),
+	// in the foreground it gets the input
+	s.send("cat &\n")
+	s.expect("[1] ")
+	time.Sleep(300 * time.Millisecond)
+	s.send("echo next\n")
+	s.expect("[1]+  Stopped                 cat")
+	s.send("fg\n")
+	time.Sleep(300 * time.Millisecond)
+	s.send("hello cat\n")
+	s.expect("hello cat\r\nhello cat")
+	s.send("\x04")
+	s.send("echo cat=$?\n")
+	s.expect("cat=0")
+
+	// Finished background jobs are reported before the next prompt
+	s.send("sleep 0.2 &\n")
+	time.Sleep(500 * time.Millisecond)
+	s.send("echo tick\n")
+	s.expect("Done                    sleep 0.2")
+
+	// exit warns about stopped jobs once
+	s.send("sleep 30\n")
+	time.Sleep(300 * time.Millisecond)
+	s.send("\x1a")
+	s.expect("Stopped")
+	s.send("exit\n")
+	s.expect("there are stopped jobs")
+	s.send("exit 0\n")
+
+	done := make(chan error, 1)
+	go func() { done <- s.cmd.Wait() }()
+	select {
+	case err := <-done:
+		if err != nil {
+			t.Errorf("shell exited with %v", err)
+		}
+	case <-time.After(5 * time.Second):
+		t.Fatal("shell did not exit")
+	}
+}

main.go

@@ -12,6 +12,7 @@ import (
 	"os/user"
 	"path/filepath"
 	"runtime/debug"
+	"sort"
 	"strconv"
 	"strings"
 	"syscall"
@@ -73,12 +74,15 @@ func versionInfo() string {
 // previousDir tracks the previous working directory for 'cd -' support
 var previousDir string
 
-// getHomeDir returns the user's home directory
+// getHomeDir returns the user's home directory: $HOME like in sh, or the
+// home directory from the user database if $HOME is not set
 func getHomeDir() string {
+	if home := os.Getenv("HOME"); home != "" {
+		return home
+	}
 	usr, err := user.Current()
 	if err != nil {
-		// Fallback to HOME environment variable
-		return os.Getenv("HOME")
+		return ""
 	}
 	return usr.HomeDir
 }
@@ -113,10 +117,12 @@ func expandTilde(path string) string {
 
 // token is a word or an operator of a command line.
 type token struct {
-	op   string // "" for a word, otherwise |, <, >, >>, >&, <&, &> or &>>
-	word string // the word, if op == ""
-	fd   int    // the redirected file descriptor (for redirections)
-	dup  int    // the target file descriptor of >& and <&
+	op      string // "" for a word, otherwise |, <, >, >>, >&, <&, &> or &>>
+	word    string // the word, if op == ""
+	pattern string // the word as glob pattern (quoted characters escaped)
+	glob    bool   // the word contains unquoted * ? or [ and is expanded
+	fd      int    // the redirected file descriptor (for redirections)
+	dup     int    // the target file descriptor of >& and <&
 }
 
 // tokenize splits input into words and operators like a (very) simple POSIX
@@ -136,7 +142,9 @@ func tokenize(input string) ([]token, error) {
 	var (
 		tokens   []token
 		b        strings.Builder
-		inWord   bool // a word has been started (even if it is still empty)
+		pat      strings.Builder // the word as glob pattern, quoted parts escaped
+		glob     bool            // the word contains unquoted * ? or [
+		inWord   bool            // a word has been started (even if it is still empty)
 		quote    byte
 		escaped  bool
 		rawStart = -1 // start of the current word in input
@@ -144,12 +152,19 @@ func tokenize(input string) ([]token, error) {
 
 	endWord := func() {
 		if inWord {
-			tokens = append(tokens, token{word: b.String()})
+			tokens = append(tokens, token{word: b.String(), pattern: pat.String(), glob: glob})
 		}
 		b.Reset()
+		pat.Reset()
+		glob = false
 		inWord = false
 		rawStart = -1
 	}
+	// literal adds quoted, escaped or expanded text: it is never a pattern
+	literal := func(s string) {
+		b.WriteString(s)
+		pat.WriteString(escapeGlob(s))
+	}
 	startRaw := func(i int) {
 		if rawStart < 0 {
 			rawStart = i
@@ -161,16 +176,16 @@ func tokenize(input string) ([]token, error) {
 		switch {
 		case escaped:
 			if quote == '"' && !strings.ContainsRune("$\"\\`", rune(ch)) {
-				b.WriteByte('\\')
+				literal("\\")
 			}
-			b.WriteByte(ch)
+			literal(string(ch))
 			inWord = true
 			escaped = false
 		case quote == '\'':
 			if ch == '\'' {
 				quote = 0
 			} else {
-				b.WriteByte(ch)
+				literal(string(ch))
 			}
 		case ch == '\\':
 			startRaw(i)
@@ -181,7 +196,9 @@ func tokenize(input string) ([]token, error) {
 			if err != nil {
 				return nil, err
 			}
-			b.WriteString(value)
+			// Expanded values are never patterns (and never split), so that
+			// e.g. a * in a variable does not match files
+			literal(value)
 			// A literal "$" counts as content, an expansion that is empty does
 			// not (unless quoted), like in sh
 			if n == 1 || value != "" {
@@ -192,7 +209,7 @@ func tokenize(input string) ([]token, error) {
 			if ch == '"' {
 				quote = 0
 			} else {
-				b.WriteByte(ch)
+				literal(string(ch))
 			}
 		case ch == '"' || ch == '\'':
 			startRaw(i)
@@ -225,6 +242,8 @@ func tokenize(input string) ([]token, error) {
 			if inWord && rawStart >= 0 && isDigits(input[rawStart:i]) {
 				fd, _ = strconv.Atoi(input[rawStart:i])
 				b.Reset()
+				pat.Reset()
+				glob = false
 				inWord = false
 				rawStart = -1
 			} else {
@@ -256,11 +275,21 @@ func tokenize(input string) ([]token, error) {
 			if home == "" {
 				home = "~"
 			}
-			b.WriteString(home)
+			literal(home)
 			inWord = true
 		default:
 			startRaw(i)
 			b.WriteByte(ch)
+			switch {
+			case ch == '*' || ch == '?' || ch == '[':
+				glob = true
+				pat.WriteByte(ch)
+			case ch == '!' && strings.HasSuffix(pat.String(), "[") && !strings.HasSuffix(pat.String(), "\\["):
+				// POSIX [!...] is [^...] in Go
+				pat.WriteByte('^')
+			default:
+				pat.WriteByte(ch)
+			}
 			inWord = true
 		}
 	}
@@ -275,6 +304,123 @@ func tokenize(input string) ([]token, error) {
 	return tokens, nil
 }
 
+// escapeGlob escapes the characters that are special in a glob pattern.
+func escapeGlob(s string) string {
+	var b strings.Builder
+	for i := 0; i < len(s); i++ {
+		if strings.IndexByte("*?[]\\", s[i]) >= 0 {
+			b.WriteByte('\\')
+		}
+		b.WriteByte(s[i])
+	}
+	return b.String()
+}
+
+// hasGlobMeta reports whether pattern contains an unescaped * ? or [.
+func hasGlobMeta(pattern string) bool {
+	for i := 0; i < len(pattern); i++ {
+		switch pattern[i] {
+		case '\\':
+			i++
+		case '*', '?', '[':
+			return true
+		}
+	}
+	return false
+}
+
+// unescapeGlob removes the escapes from a pattern without wildcards.
+func unescapeGlob(pattern string) string {
+	var b strings.Builder
+	for i := 0; i < len(pattern); i++ {
+		if pattern[i] == '\\' && i+1 < len(pattern) {
+			i++
+		}
+		b.WriteByte(pattern[i])
+	}
+	return b.String()
+}
+
+// expandGlob returns the paths matching pattern, sorted. Like sh, * and ?
+// do not match a leading dot (hidden files), unless the pattern component
+// starts with a dot, and a trailing / only matches directories. An invalid
+// pattern matches nothing.
+func expandGlob(pattern string) []string {
+	paths := []string{""}
+	if strings.HasPrefix(pattern, "/") {
+		paths = []string{"/"}
+	}
+	components := strings.Split(strings.Trim(pattern, "/"), "/")
+	join := func(dir, name string) string {
+		if dir == "" || strings.HasSuffix(dir, "/") {
+			return dir + name
+		}
+		return dir + "/" + name
+	}
+
+	for _, comp := range components {
+		if comp == "" {
+			continue // a//b
+		}
+		var next []string
+		for _, dir := range paths {
+			if !hasGlobMeta(comp) {
+				p := join(dir, unescapeGlob(comp))
+				if _, err := os.Lstat(p); err == nil {
+					next = append(next, p)
+				}
+				continue
+			}
+			readDir := dir
+			if readDir == "" {
+				readDir = "."
+			}
+			entries, err := os.ReadDir(readDir)
+			if err != nil {
+				continue
+			}
+			for _, e := range entries {
+				name := e.Name()
+				if strings.HasPrefix(name, ".") && !strings.HasPrefix(comp, ".") && !strings.HasPrefix(comp, "\\.") {
+					continue
+				}
+				ok, err := filepath.Match(comp, name)
+				if err != nil {
+					return nil
+				}
+				if ok {
+					next = append(next, join(dir, name))
+				}
+			}
+		}
+		paths = next
+	}
+
+	if strings.HasSuffix(pattern, "/") {
+		var dirs []string
+		for _, p := range paths {
+			if info, err := os.Stat(p); err == nil && info.IsDir() {
+				dirs = append(dirs, p+"/")
+			}
+		}
+		paths = dirs
+	}
+	sort.Strings(paths)
+	return paths
+}
+
+// expandWord returns the words a token expands to: the matching paths for
+// a pattern, or the word itself if it is no pattern or nothing matches (like
+// in sh).
+func expandWord(t token) []string {
+	if t.glob {
+		if matches := expandGlob(t.pattern); len(matches) > 0 {
+			return matches
+		}
+	}
+	return []string{t.word}
+}
+
 // isDigits reports whether s is a non-empty string of ASCII digits.
 func isDigits(s string) bool {
 	if s == "" {
@@ -556,7 +702,7 @@ type shellCompleter struct {
 
 func newShellCompleter() *shellCompleter {
 	return &shellCompleter{
-		commands: []string{"cd", "pwd", "echo", "exit", "quit", "set", "export", "help"},
+		commands: []string{"cd", "pwd", "echo", "exit", "quit", "set", "export", "source", "jobs", "fg", "bg", "wait", "alias", "unalias", "help"},
 	}
 }
 
@@ -580,7 +726,8 @@ func (c *shellCompleter) Do(line []rune, pos int) ([][]rune, int) {
 		// Complete commands
 		var candidates [][]rune
 		seen := make(map[string]bool)
-		for _, cmd := range append(c.commands, pathExecutables(word)...) {
+		names := append(append(append([]string(nil), c.commands...), aliasNames()...), pathExecutables(word)...)
+		for _, cmd := range names {
 			if strings.HasPrefix(cmd, word) && !seen[cmd] {
 				seen[cmd] = true
 				candidates = append(candidates, []rune(escapeWord(cmd[len(word):])+" "))
@@ -668,7 +815,7 @@ func currentWord(s string) (word string, start int, quote byte) {
 func escapeWord(s string) string {
 	var b strings.Builder
 	for _, r := range s {
-		if strings.ContainsRune(" \t\\'\";|&<>", r) {
+		if strings.ContainsRune(" \t\\'\";|&<>*?[$", r) {
 			b.WriteByte('\\')
 		}
 		b.WriteRune(r)
@@ -723,33 +870,48 @@ func completeFilePath(line, prefix string) []string {
 	return matches
 }
 
-const usage = `usage: gosh [-l] [-i] [script]
-       gosh [-l] -c command
+const usage = `usage: gosh [-l] [-i] [--norc] [--noprofile] [script]
+       gosh [-l] [--noprofile] -c command
        gosh -version`
 
+// sysConfDir holds the system-wide startup files.
+var sysConfDir = "/etc/gosh"
+
 func main() {
-	os.Exit(run(os.Args[1:]))
+	args := os.Args[1:]
+	// login(1), sshd and "su -" start a login shell with a leading - in
+	// argv[0], e.g. "-gosh"
+	if strings.HasPrefix(os.Args[0], "-") {
+		args = append([]string{"-l"}, args...)
+	}
+	os.Exit(run(args))
 }
 
 // run parses the command line and runs gosh in the matching mode. It returns
 // the exit status of the shell.
 func run(args []string) int {
-	// -l/--login is accepted for compatibility (e.g. "su -l", login(1)), but
-	// gosh does not read a startup file yet. -i forces interactive mode even
-	// if stdin is not a terminal.
-	forceInteractive := false
+	var login, forceInteractive, noRC, noProfile bool
 flags:
 	for len(args) > 0 {
 		switch args[0] {
 		case "-l", "--login":
+			login = true
 		case "-i":
+			// Interactive mode even if stdin is not a terminal
 			forceInteractive = true
+		case "--norc":
+			noRC = true
+		case "--noprofile":
+			noProfile = true
 		default:
 			break flags
 		}
 		args = args[1:]
 	}
 
+	// Determine what to run, before the startup files are read
+	var script func() int
+	interactiveMode := false
 	if len(args) > 0 {
 		switch arg := args[0]; {
 		case arg == "-version" || arg == "--version" || arg == "-V":
@@ -766,13 +928,13 @@ flags:
 				fmt.Fprintln(os.Stderr, usage)
 				return 2
 			}
-			return runScript(strings.NewReader(args[1]))
+			script = func() int { return runScript(strings.NewReader(args[1]), "") }
 		case strings.HasPrefix(arg, "-") && arg != "-":
 			fmt.Fprintf(os.Stderr, "gosh: %s: invalid option\n", arg)
 			fmt.Fprintln(os.Stderr, usage)
 			return 2
 		case arg == "-":
-			return runScript(os.Stdin)
+			script = func() int { return runScript(os.Stdin, "") }
 		default:
 			f, err := os.Open(arg)
 			if err != nil {
@@ -780,30 +942,109 @@ flags:
 				return 127
 			}
 			defer f.Close()
-			return runScript(bufio.NewReader(f))
+			script = func() int { return runScript(bufio.NewReader(f), arg) }
 		}
+	} else if forceInteractive || readline.IsTerminal(int(os.Stdin.Fd())) {
+		interactiveMode = true
+	} else {
+		// Without a terminal (e.g. "echo ls | gosh") read the commands from
+		// stdin
+		script = func() int { return runScript(os.Stdin, "") }
 	}
 
-	// Without a terminal (e.g. "echo ls | gosh") read the commands from stdin.
-	if !forceInteractive && !readline.IsTerminal(int(os.Stdin.Fd())) {
-		return runScript(os.Stdin)
+	// Aliases are expanded in interactive shells, also in their startup files
+	interactiveShell = interactiveMode
+	for _, file := range startupFiles(login && !noProfile, interactiveMode && !noRC) {
+		sourceStartupFile(file)
 	}
 
+	if !interactiveMode {
+		return script()
+	}
 	interactive()
 	return 0
 }
 
+// startupFiles returns the startup files to read, in order: for login
+// shells /etc/gosh/profile and ~/.gosh_profile, for interactive shells
+// /etc/gosh/goshrc and ~/.goshrc. Non-interactive shells (gosh -c, scripts)
+// read no files unless they are login shells.
+func startupFiles(login, interactive bool) []string {
+	home := getHomeDir()
+	var files []string
+	if login {
+		files = append(files, filepath.Join(sysConfDir, "profile"))
+		if home != "" {
+			files = append(files, filepath.Join(home, ".gosh_profile"))
+		}
+	}
+	if interactive {
+		files = append(files, filepath.Join(sysConfDir, "goshrc"))
+		if home != "" {
+			files = append(files, filepath.Join(home, ".goshrc"))
+		}
+	}
+	return files
+}
+
+// sourceStartupFile runs a startup file in the current shell. A missing file
+// is skipped silently, other errors are reported.
+func sourceStartupFile(path string) {
+	f, err := os.Open(path)
+	if errors.Is(err, fs.ErrNotExist) {
+		return
+	}
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "gosh:", err)
+		return
+	}
+	defer f.Close()
+	runScript(bufio.NewReader(f), path)
+}
+
+// sourceDepth counts nested source commands, to stop a file that sources
+// itself.
+var sourceDepth int
+
+// sourceFile runs the commands of a file in the current shell (the source and
+// . builtins) and returns an error carrying the status of the last command.
+func sourceFile(cmd, path string) error {
+	if sourceDepth >= 100 {
+		return fmt.Errorf("%s: %s: maximum nesting depth exceeded", cmd, sanitize(path))
+	}
+	f, err := os.Open(path)
+	if err != nil {
+		var pathErr *fs.PathError
+		if errors.As(err, &pathErr) {
+			err = pathErr.Err
+		}
+		return fmt.Errorf("%s: %s: %v", cmd, sanitize(path), err)
+	}
+	defer f.Close()
+
+	sourceDepth++
+	defer func() { sourceDepth-- }()
+	if status := runScript(bufio.NewReader(f), path); status != 0 {
+		return statusError(status)
+	}
+	return nil
+}
+
 // runScript executes the commands from r line by line. Like sh, it does not
 // stop at a failing command and returns the exit status of the last one.
 // Empty lines and lines starting with # (e.g. a #!/usr/bin/gosh line) are
-// skipped.
-func runScript(r io.Reader) int {
+// skipped. If name is set, errors are reported with file name and line.
+func runScript(r io.Reader, name string) int {
 	status := 0
-	for {
+	for lineNo := 1; ; lineNo++ {
 		line, err := readLine(r)
 		if trimmed := strings.TrimSpace(line); trimmed != "" && !strings.HasPrefix(trimmed, "#") {
-			printError(execInput(line))
+			cmdErr := execInput(line)
 			status = lastStatus
+			if name != "" && cmdErr != nil {
+				cmdErr = fmt.Errorf("%s:%d: %w", sanitize(name), lineNo, cmdErr)
+			}
+			printError(cmdErr)
 		}
 		if err != nil {
 			if err != io.EOF {
@@ -871,6 +1112,10 @@ func exitStatus(err error) int {
 // interactive runs the interactive shell with line editing, history and
 // completion until the user exits.
 func interactive() {
+	interactiveShell = true
+	initJobControl()
+	defer releaseTerminal()
+
 	// Ctrl+C sends SIGINT to the whole foreground process group. Catch it so
 	// that it only stops the running command and not the shell. (signal.Ignore
 	// would be inherited by the child processes.)
@@ -901,6 +1146,9 @@ func interactive() {
 
 	// Main loop
 	for {
+		// Report finished and stopped background jobs
+		reapJobs(true)
+
 		// Update prompt dynamically (in case directory changed)
 		l.SetPrompt(getPrompt())
 		
@@ -913,6 +1161,11 @@ func interactive() {
 			// Handle EOF (Ctrl+D)
 			if err == io.EOF {
 				fmt.Println()
+				if hasStoppedJobs() && !exitWarned {
+					exitWarned = true
+					fmt.Fprintln(os.Stderr, "gosh: there are stopped jobs")
+					continue
+				}
 				break
 			}
 			fmt.Fprintln(os.Stderr, "Error reading input:", err)
@@ -973,11 +1226,12 @@ func printError(err error) {
 // listItem is a command of a command list together with the operator that
 // connects it to the previous command ("" for the first one).
 type listItem struct {
-	op      string // "", ";", "&&" or "||"
-	command string
+	op         string // "", ";", "&&" or "||"
+	command    string
+	background bool // the command ends with &
 }
 
-// splitList splits input at unquoted ;, && and ||. Quotes, escapes, ${...}
+// splitList splits input at unquoted ;, &, && and ||. Quotes, escapes, ${...}
 // and comments are handled like in splitWords, but nothing is expanded yet:
 // that happens per command when it runs, so "cd /tmp && echo $PWD" works.
 func splitList(input string) ([]listItem, error) {
@@ -1037,6 +1291,17 @@ scan:
 		case ch == '#' && isWordStart:
 			end = i
 			break scan
+		case ch == '&' && !(i+1 < len(input) && strings.IndexByte("&>", input[i+1]) >= 0) &&
+			!(i > 0 && strings.IndexByte("<>", input[i-1]) >= 0):
+			// A single & (not &&, &>, >& or <&) runs the command in the
+			// background
+			if err := add(i, "&"); err != nil {
+				return nil, err
+			}
+			items[len(items)-1].background = true
+			op = ";"
+			start = i + 1
+			wordStart = true
 		case ch == ';',
 			ch == '&' && i+1 < len(input) && input[i+1] == '&',
 			ch == '|' && i+1 < len(input) && input[i+1] == '|':
@@ -1065,6 +1330,9 @@ scan:
 // and ||. It returns the error of the last command that was run; errors of
 // earlier commands are printed. $? is updated after each command.
 func execInput(input string) error {
+	if interactiveShell {
+		input = expandAliases(input)
+	}
 	items, err := splitList(input)
 	if err != nil {
 		lastStatus = exitStatus(err)
@@ -1077,14 +1345,15 @@ func execInput(input string) error {
 			continue
 		}
 		printError(lastErr)
-		lastErr = execCommand(item.command)
+		lastErr = execCommand(item.command, item.background)
 		lastStatus = exitStatus(lastErr)
 	}
 	return lastErr
 }
 
-// execCommand executes a pipeline of simple commands with redirections.
-func execCommand(input string) error {
+// execCommand executes a pipeline of simple commands with redirections, in
+// the background if background is set.
+func execCommand(input string, background bool) error {
 	// Split the input into words and operators, expanding variables and ~ on
 	// the way.
 	tokens, err := tokenize(input)
@@ -1102,7 +1371,11 @@ func execCommand(input string) error {
 	if len(stages) == 0 {
 		return nil
 	}
-	return runPipeline(stages)
+	// "exit" with stopped jobs only warns, unless it is repeated right away
+	if name := stages[0].args; len(name) == 0 || (name[0] != "exit" && name[0] != "quit") {
+		exitWarned = false
+	}
+	return runPipeline(stages, strings.TrimSpace(input), background)
 }
 
 // redirect is a redirection of a simple command, e.g. 2>>file or 2>&1.
@@ -1131,7 +1404,7 @@ func parsePipeline(tokens []token) ([]stage, error) {
 		t := tokens[i]
 		switch t.op {
 		case "":
-			cur.args = append(cur.args, t.word)
+			cur.args = append(cur.args, expandWord(t)...)
 		case "|":
 			if isEmpty(cur) {
 				return nil, syntaxError("|")
@@ -1148,7 +1421,11 @@ func parsePipeline(tokens []token) ([]stage, error) {
 				return nil, syntaxError(next.op)
 			}
 			i++
-			cur.redirects = append(cur.redirects, redirect{op: t.op, fd: t.fd, file: tokens[i].word})
+			files := expandWord(tokens[i])
+			if len(files) > 1 {
+				return nil, fmt.Errorf("%s: ambiguous redirect", sanitize(tokens[i].word))
+			}
+			cur.redirects = append(cur.redirects, redirect{op: t.op, fd: t.fd, file: files[0]})
 		}
 	}
 
@@ -1161,49 +1438,71 @@ func parsePipeline(tokens []token) ([]stage, error) {
 	return append(stages, cur), nil
 }
 
-// runPipeline runs the stages of a pipeline concurrently, connecting the
-// stdout of each stage to the stdin of the next one. It returns the error of
-// the last stage (so $? is its exit status, like in sh); errors of the other
-// stages are printed.
-func runPipeline(stages []stage) error {
-	waits := make([]func() error, len(stages))
+// runPipeline runs the stages of a pipeline concurrently as a job,
+// connecting the stdout of each stage to the stdin of the next one. In the
+// foreground it waits for the job and returns the error of the last stage (so
+// $? is its exit status, like in sh); errors of the other stages are printed.
+// In the background it adds the job to the job table and returns nil.
+func runPipeline(stages []stage, text string, background bool) error {
+	j := &job{text: text}
+	if jobControl && !background {
+		shellTTY, _ = readline.GetState(ttyFd)
+	}
+
 	stdin := os.Stdin
+	if background && !jobControl {
+		// Without job control background jobs must not read from the
+		// terminal, like in sh
+		if devNull, err := os.Open(os.DevNull); err == nil {
+			stdin = devNull
+		}
+	}
+	var startErr error
 	for i, st := range stages {
 		stdout := os.Stdout
 		var next *os.File
 		if i < len(stages)-1 {
 			r, w, err := os.Pipe()
 			if err != nil {
-				// Let the stages that already run finish
 				if stdin != os.Stdin {
 					stdin.Close()
 				}
-				for _, wait := range waits[:i] {
-					printError(wait())
-				}
-				return err
+				startErr = err
+				break
 			}
 			stdout, next = w, r
 		}
-		waits[i] = startStage(st, stdin, stdout, len(stages) > 1)
+		j.procs = append(j.procs, startStage(st, stdin, stdout, j, len(stages) > 1, background))
 		stdin = next
 	}
-
-	var err error
-	for i, wait := range waits {
-		err = wait()
-		if i < len(waits)-1 {
-			printError(err)
+	if startErr != nil {
+		// Let the stages that already run finish
+		if len(j.procs) > 0 {
+			waitForeground(j)
 		}
+		return startErr
 	}
-	return err
+
+	if background {
+		addJob(j)
+		if interactiveShell {
+			pid := 0
+			for _, p := range j.procs {
+				if p.cmd != nil {
+					pid = p.cmd.Process.Pid
+				}
+			}
+			fmt.Fprintf(os.Stderr, "[%d] %d\n", j.id, pid)
+		}
+		return nil
+	}
+	return waitForeground(j)
 }
 
-// startStage starts a stage of a pipeline with the given stdin and stdout and
-// returns a function that waits for it to finish. Pipe ends passed in are
-// closed by startStage once the stage no longer needs them, so that the
-// neighbors see EOF or get SIGPIPE.
-func startStage(st stage, stdin, stdout *os.File, inPipeline bool) func() error {
+// startStage starts a stage of the pipeline of job j with the given stdin and
+// stdout. Pipe ends passed in are closed by startStage once the stage no
+// longer needs them, so that the neighbors see EOF or get SIGPIPE.
+func startStage(st stage, stdin, stdout *os.File, j *job, inPipeline, background bool) *proc {
 	var owned []*os.File
 	if stdin != os.Stdin {
 		owned = append(owned, stdin)
@@ -1216,9 +1515,6 @@ func startStage(st stage, stdin, stdout *os.File, inPipeline bool) func() error
 			f.Close()
 		}
 	}
-	result := func(err error) func() error {
-		return func() error { return err }
-	}
 
 	// Connect the command to the terminal unless redirected. Without Stdin
 	// the command would read from /dev/null, so interactive programs (su,
@@ -1230,13 +1526,17 @@ func startStage(st stage, stdin, stdout *os.File, inPipeline bool) func() error
 	if err != nil || len(st.args) == 0 {
 		// A command without arguments only creates or truncates the files
 		closeOwned()
-		return result(err)
+		return finishedProc(err)
 	}
 
 	if builtin, ok := builtins[st.args[0]]; ok {
-		if inPipeline && builtin.changesState {
+		switch {
+		case inPipeline && builtin.changesState:
 			closeOwned()
-			return result(fmt.Errorf("%s: cannot be used in a pipeline", st.args[0]))
+			return finishedProc(fmt.Errorf("%s: cannot be used in a pipeline", st.args[0]))
+		case background && builtin.changesState:
+			closeOwned()
+			return finishedProc(fmt.Errorf("%s: cannot be run in the background", st.args[0]))
 		}
 		run := func() error {
 			defer closeOwned()
@@ -1248,16 +1548,29 @@ func startStage(st stage, stdin, stdout *os.File, inPipeline bool) func() error
 			}
 			return err
 		}
-		if !inPipeline {
-			return result(run())
+		if !inPipeline && !background {
+			return finishedProc(run())
 		}
-		done := make(chan error, 1)
-		go func() { done <- run() }()
-		return func() error { return <-done }
+		p := &proc{done: make(chan error, 1)}
+		go func() { p.done <- run() }()
+		return p
 	}
 
 	cmd := exec.Command(st.args[0], st.args[1:]...)
 	cmd.Stdin, cmd.Stdout, cmd.Stderr = fds[0], fds[1], fds[2]
+	if jobControl {
+		// All processes of the job share a process group: the one of the
+		// first process. In the foreground, the first process makes its
+		// group the foreground group of the terminal before it starts the
+		// program, so that it can use the terminal right away.
+		attr := &syscall.SysProcAttr{Setpgid: true, Pgid: j.pgid}
+		if j.pgid == 0 && !background {
+			if ctty := ttyIndex(fds); ctty >= 0 {
+				attr.Foreground, attr.Ctty = true, ctty
+			}
+		}
+		cmd.SysProcAttr = attr
+	}
 	err = cmd.Start()
 	// The child has its own copies of the files now
 	closeOwned()
@@ -1265,9 +1578,16 @@ func startStage(st stage, stdin, stdout *os.File, inPipeline bool) func() error
 		err = fmt.Errorf("%s: %w", sanitize(st.args[0]), errCommandNotFound)
 	}
 	if err != nil {
-		return result(err)
+		return finishedProc(err)
 	}
-	return cmd.Wait
+	if jobControl && j.pgid == 0 {
+		j.pgid = cmd.Process.Pid
+		if !background {
+			// In case the process could not do it (no terminal in fds)
+			setForeground(j.pgid)
+		}
+	}
+	return &proc{cmd: cmd}
 }
 
 // applyRedirects applies the redirections in order to fds (stdin, stdout,
@@ -1322,13 +1642,21 @@ func applyRedirects(fds *[3]*os.File, redirects []redirect) ([]*os.File, error)
 // the shell cannot be used in a pipeline, since there they would run
 // concurrently (sh runs them in a subshell where they have no effect).
 var builtins = map[string]struct{ changesState bool }{
-	"cd":     {changesState: true},
-	"pwd":    {},
-	"exit":   {changesState: true},
-	"quit":   {changesState: true},
-	"set":    {changesState: true},
-	"export": {changesState: true},
-	"help":   {},
+	"cd":      {changesState: true},
+	"pwd":     {},
+	"exit":    {changesState: true},
+	"quit":    {changesState: true},
+	"set":     {changesState: true},
+	"export":  {changesState: true},
+	"help":    {},
+	"source":  {changesState: true},
+	".":       {changesState: true},
+	"jobs":    {},
+	"fg":      {changesState: true},
+	"bg":      {changesState: true},
+	"wait":    {changesState: true},
+	"alias":   {},
+	"unalias": {changesState: true},
 }
 
 // runBuiltin executes a built-in command, writing its output to stdout.
@@ -1373,17 +1701,17 @@ func runBuiltin(args []string, stdout io.Writer) error {
 		if len(args) > 1 {
 			var exitCode int
 			fmt.Sscanf(args[1], "%d", &exitCode)
-			os.Exit(exitCode)
+			return exitShell(exitCode)
 		}
-		os.Exit(lastStatus)
+		return exitShell(lastStatus)
 	case "quit":
 		// quit with optional status code
 		if len(args) > 1 {
 			var exitCode int
 			fmt.Sscanf(args[1], "%d", &exitCode)
-			os.Exit(exitCode)
+			return exitShell(exitCode)
 		}
-		os.Exit(lastStatus)
+		return exitShell(lastStatus)
 	case "set":
 		// set VAR=value - set environment variable
 		if len(args) < 2 {
@@ -1408,6 +1736,24 @@ func runBuiltin(args []string, stdout io.Writer) error {
 		}
 		os.Setenv(parts[0], parts[1])
 		return nil
+	case "alias":
+		return builtinAlias(args, stdout)
+	case "unalias":
+		return builtinUnalias(args)
+	case "jobs":
+		return builtinJobs(stdout)
+	case "fg":
+		return builtinFg(args, stdout)
+	case "bg":
+		return builtinBg(args, stdout)
+	case "wait":
+		return builtinWait(args)
+	case "source", ".":
+		// source file - run the commands of file in the current shell
+		if len(args) < 2 {
+			return fmt.Errorf("usage: %s file", args[0])
+		}
+		return sourceFile(args[0], args[1])
 	case "help":
 		fmt.Fprintln(stdout, "gosh - Go Shell\nVersion: " + versionInfo() + `
 
@@ -1419,6 +1765,13 @@ Built-in commands:
   quit [code]   - Quit shell with status code (default: $?)
   set VAR=val   - Set environment variable
   export VAR=val - Export environment variable
+  source file   - Run the commands of file in this shell (also: . file)
+  jobs          - List background and stopped jobs
+  fg [%n]       - Continue job n (default: current job) in the foreground
+  bg [%n]       - Continue stopped job n in the background
+  wait [%n]     - Wait for job n or all background jobs
+  alias [name[=value] ...] - Define or show aliases (alias ll='ls -l')
+  unalias name  - Remove an alias (unalias -a: all aliases)
   help          - Show this help
 
 Features:
@@ -1430,6 +1783,9 @@ Features:
     override with $GOSH_HISTFILE); lines starting with a space are not saved
   - Tab completion for commands and file paths
   - Tilde expansion (~, ~/path) at the start of unquoted words
+  - Wildcards: * ? [abc] [a-z] [!abc] match file names (not hidden files
+    unless the pattern starts with a dot); quoted wildcards and values of
+    variables are not expanded, a pattern without match is kept as is
   - Colored prompt (user@host green, red for root; directory blue),
     configurable with $GOSH_COLORS, e.g. GOSH_COLORS='user=1;33:path=36'
     (keys user, root, path; values are ANSI SGR codes, empty = no color);
@@ -1440,8 +1796,15 @@ Features:
     a || b (b only if a failed); $? is the exit status of the last command
   - Pipes (a | b) and redirections: < file, > file, >> file, 2> file,
     2>> file, 2>&1, >&2, &> file (stdout and stderr), &>> file
+  - Job control: command & runs in the background, Ctrl+Z stops the
+    foreground job; jobs, fg, bg and wait manage the jobs
+  - Aliases replace the first word of a command in interactive shells
+    (define them in ~/.goshrc); \name or 'name' skips the alias
   - Non-interactive use: gosh -c 'command', gosh script, command | gosh;
-    the exit status is the one of the last command`)
+    the exit status is the one of the last command
+  - Startup files: login shells (-l or argv[0] starting with -) read
+    /etc/gosh/profile and ~/.gosh_profile, interactive shells read
+    /etc/gosh/goshrc and ~/.goshrc (skip with --noprofile, --norc)`)
 		return nil
 	}
 	return fmt.Errorf("%s: not a builtin", args[0])

main_test.go

@@ -226,7 +226,7 @@ func TestShell_EndToEnd(t *testing.T) {
 
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
-			cmd := exec.Command("go", "run", "main.go")
+			cmd := exec.Command("go", "run", ".")
 			cmd.Stdin = strings.NewReader(tc.input)
 			var stdout, stderr bytes.Buffer
 			cmd.Stdout = &stdout
@@ -259,7 +259,7 @@ func TestShell_EOF_ExitsGracefully(t *testing.T) {
 	// Simulate EOF by sending empty input
 	// Note: When using piped input, readline doesn't print prompts
 	// So we just verify the shell exits cleanly
-	cmd := exec.Command("go", "run", "main.go")
+	cmd := exec.Command("go", "run", ".")
 	cmd.Stdin = strings.NewReader("")
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -278,7 +278,7 @@ func TestShell_EOF_ExitsGracefully(t *testing.T) {
 func TestShell_EOF_AfterCommand(t *testing.T) {
 	// Test that EOF after a command works
 	// Note: When using piped input, readline doesn't print prompts
-	cmd := exec.Command("go", "run", "main.go")
+	cmd := exec.Command("go", "run", ".")
 	cmd.Stdin = strings.NewReader("echo test\n")
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -302,7 +302,7 @@ func TestShell_SIGINT_HandlerSetup(t *testing.T) {
 	// This test verifies that the shell doesn't panic when receiving signals
 	// We can't easily test SIGINT handling from a test, but we can verify
 	// the shell runs without crashing
-	cmd := exec.Command("go", "run", "main.go")
+	cmd := exec.Command("go", "run", ".")
 	cmd.Stdin = strings.NewReader("echo test\nquit\n")
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -458,7 +458,7 @@ func TestShell_ExitWithStatusCode(t *testing.T) {
 	}
 	
 	// Build the binary once
-	build := exec.Command("go", "build", "-o", "gosh_test", "main.go")
+	build := exec.Command("go", "build", "-o", "gosh_test", ".")
 	if err := build.Run(); err != nil {
 		t.Fatalf("failed to build: %v", err)
 	}
@@ -494,7 +494,7 @@ func TestShell_ExitWithStatusCode(t *testing.T) {
 // =============================================================================
 
 func TestShell_EnvExpansion_Home(t *testing.T) {
-	cmd := exec.Command("go", "run", "main.go")
+	cmd := exec.Command("go", "run", ".")
 	cmd.Stdin = strings.NewReader("echo $HOME\nexit\n")
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -513,7 +513,7 @@ func TestShell_EnvExpansion_Home(t *testing.T) {
 }
 
 func TestShell_EnvExpansion_Path(t *testing.T) {
-	cmd := exec.Command("go", "run", "main.go")
+	cmd := exec.Command("go", "run", ".")
 	cmd.Stdin = strings.NewReader("echo $PATH\nexit\n")
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -532,7 +532,7 @@ func TestShell_EnvExpansion_Path(t *testing.T) {
 }
 
 func TestShell_EnvExpansion_Braces(t *testing.T) {
-	cmd := exec.Command("go", "run", "main.go")
+	cmd := exec.Command("go", "run", ".")
 	cmd.Stdin = strings.NewReader("echo ${HOME}\nexit\n")
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -551,7 +551,7 @@ func TestShell_EnvExpansion_Braces(t *testing.T) {
 }
 
 func TestShell_EnvExpansion_CdWithVar(t *testing.T) {
-	cmd := exec.Command("go", "run", "main.go")
+	cmd := exec.Command("go", "run", ".")
 	cmd.Stdin = strings.NewReader("cd $HOME\npwd\nexit\n")
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -570,7 +570,7 @@ func TestShell_EnvExpansion_CdWithVar(t *testing.T) {
 }
 
 func TestShell_TildeExpansion_Ls(t *testing.T) {
-	cmd := exec.Command("go", "run", "main.go")
+	cmd := exec.Command("go", "run", ".")
 	cmd.Stdin = strings.NewReader("ls ~\nexit\n")
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -889,6 +889,9 @@ func TestMain(m *testing.M) {
 		panic(err)
 	}
 	os.Setenv("GOSH_HISTFILE", filepath.Join(dir, "history"))
+	// Never read the system's startup files; tests that read the user's
+	// files set $HOME themselves
+	sysConfDir = filepath.Join(dir, "etc")
 	code := m.Run()
 	os.RemoveAll(dir)
 	os.Exit(code)
@@ -1183,7 +1186,7 @@ func TestShell_History(t *testing.T) {
 	histFile := filepath.Join(t.TempDir(), "gosh", "history")
 	workDir := t.TempDir()
 
-	cmd := exec.Command(bin, "-i")
+	cmd := exec.Command(bin, "-i", "--norc")
 	cmd.Dir = workDir
 	cmd.Env = append(os.Environ(), "GOSH_HISTFILE="+histFile)
 	cmd.Stdin = strings.NewReader("echo first\n set SECRET=hunter2\nexit\n")
@@ -1215,7 +1218,7 @@ func TestShell_History(t *testing.T) {
 func TestShell_SIGINTKillsOnlyChild(t *testing.T) {
 	bin := buildShell(t)
 
-	cmd := exec.Command(bin, "-i")
+	cmd := exec.Command(bin, "-i", "--norc")
 	// Own process group, so that we can signal it like the terminal does
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
 	stdin, err := cmd.StdinPipe()
@@ -1313,7 +1316,7 @@ func TestRunScript(t *testing.T) {
 		"touch first\n" +
 		"false\n" +
 		"touch second" // no trailing newline
-	if got := runScript(strings.NewReader(script)); got != 0 {
+	if got := runScript(strings.NewReader(script), ""); got != 0 {
 		t.Errorf("runScript() = %d, want 0", got)
 	}
 	for _, name := range []string{"first", "second"} {
@@ -1323,7 +1326,7 @@ func TestRunScript(t *testing.T) {
 	}
 
 	// The status of the last command is returned
-	if got := runScript(strings.NewReader("true\nsh -c 'exit 3'\n")); got != 3 {
+	if got := runScript(strings.NewReader("true\nsh -c 'exit 3'\n"), ""); got != 3 {
 		t.Errorf("runScript() = %d, want 3", got)
 	}
 }
@@ -1335,7 +1338,7 @@ func TestRun_Options(t *testing.T) {
 	}{
 		{[]string{"-c", "true"}, 0},
 		{[]string{"-c", "false"}, 1},
-		{[]string{"-l", "-c", "sh -c 'exit 5'"}, 5},
+		{[]string{"-l", "--noprofile", "-c", "sh -c 'exit 5'"}, 5},
 		{[]string{"-c"}, 2},
 		{[]string{"-x"}, 2},
 		{[]string{"/gosh/no/such/script"}, 127},
@@ -1366,16 +1369,23 @@ func TestSplitList(t *testing.T) {
 		{"", nil},
 		{"   ", nil},
 		{"# only a comment", nil},
-		{"ls", []listItem{{"", "ls"}}},
-		{"a; b", []listItem{{"", "a"}, {";", " b"}}},
-		{"a;", []listItem{{"", "a"}}},
-		{"a && b || c", []listItem{{"", "a "}, {"&&", " b "}, {"||", " c"}}},
-		{`echo "a;b" 'c&&d' e\;f`, []listItem{{"", `echo "a;b" 'c&&d' e\;f`}}},
-		{`echo "x\"; y"`, []listItem{{"", `echo "x\"; y"`}}},
-		{"echo ${X:-a;b}; c", []listItem{{"", "echo ${X:-a;b}"}, {";", " c"}}},
-		{"echo a # b; c", []listItem{{"", "echo a "}}},
-		{"echo a#b; c", []listItem{{"", "echo a#b"}, {";", " c"}}},
-		{"echo a|b", []listItem{{"", "echo a|b"}}},
+		{"ls", []listItem{{"", "ls", false}}},
+		{"a; b", []listItem{{"", "a", false}, {";", " b", false}}},
+		{"a;", []listItem{{"", "a", false}}},
+		{"a && b || c", []listItem{{"", "a ", false}, {"&&", " b ", false}, {"||", " c", false}}},
+		{`echo "a;b" 'c&&d' e\;f`, []listItem{{"", `echo "a;b" 'c&&d' e\;f`, false}}},
+		{`echo "x\"; y"`, []listItem{{"", `echo "x\"; y"`, false}}},
+		{"echo ${X:-a;b}; c", []listItem{{"", "echo ${X:-a;b}", false}, {";", " c", false}}},
+		{"echo a # b; c", []listItem{{"", "echo a ", false}}},
+		{"echo a#b; c", []listItem{{"", "echo a#b", false}, {";", " c", false}}},
+		{"echo a|b", []listItem{{"", "echo a|b", false}}},
+		{"a & b", []listItem{{"", "a ", true}, {";", " b", false}}},
+		{"a &", []listItem{{"", "a ", true}}},
+		{"a&", []listItem{{"", "a", true}}},
+		{"a 2>&1 &", []listItem{{"", "a 2>&1 ", true}}},
+		{"a &> f &", []listItem{{"", "a &> f ", true}}},
+		{"a >&2 && b", []listItem{{"", "a >&2 ", false}, {"&&", " b", false}}},
+		{`echo "a & b" \&`, []listItem{{"", `echo "a & b" \&`, false}}},
 	}
 	for _, tc := range tests {
 		got, err := splitList(tc.input)
@@ -1384,13 +1394,13 @@ func TestSplitList(t *testing.T) {
 			continue
 		}
 		if !reflect.DeepEqual(got, tc.want) {
-			t.Errorf("splitList(%q) = %q, want %q", tc.input, got, tc.want)
+			t.Errorf("splitList(%q) = %+v, want %+v", tc.input, got, tc.want)
 		}
 	}
 }
 
 func TestSplitList_SyntaxErrors(t *testing.T) {
-	for _, input := range []string{"; a", "a ;; b", "&& a", "a &&", "a ||", "a && ; b", "a || && b"} {
+	for _, input := range []string{"; a", "a ;; b", "&& a", "a &&", "a ||", "a && ; b", "a || && b", "& a", "a & && b", "a & & b"} {
 		if _, err := splitList(input); err == nil || !strings.Contains(err.Error(), "syntax error") {
 			t.Errorf("splitList(%q) = %v, want syntax error", input, err)
 		}
@@ -1514,6 +1524,10 @@ func TestTokenize_Operators(t *testing.T) {
 			t.Errorf("tokenize(%q) returned error: %v", tc.input, err)
 			continue
 		}
+		// Patterns are tested in TestTokenize_Patterns
+		for i := range got {
+			got[i].pattern, got[i].glob = "", false
+		}
 		if !reflect.DeepEqual(got, tc.want) {
 			t.Errorf("tokenize(%q) = %+v, want %+v", tc.input, got, tc.want)
 		}
@@ -1620,3 +1634,303 @@ func TestExecInput_RedirectionErrors(t *testing.T) {
 		t.Error("file f must not be created for a bad file descriptor")
 	}
 }
+
+func TestTokenize_Patterns(t *testing.T) {
+	t.Setenv("GOSH_GLOB", "*.go")
+	tests := []struct {
+		input   string
+		pattern string
+		glob    bool
+	}{
+		{"*.go", "*.go", true},
+		{"a?c", "a?c", true},
+		{"[ab].go", "[ab].go", true},
+		{"[!a].go", "[^a].go", true},
+		{"plain", "plain", false},
+		// Quoted, escaped and expanded characters are literal
+		{`"*.go"`, `\*.go`, false},
+		{`'*'.go`, `\*.go`, false},
+		{`\*.go`, `\*.go`, false},
+		{`"x"*`, `x*`, true},
+		{"$GOSH_GLOB", `\*.go`, false},
+		{`'['!a].go`, `\[!a].go`, false},
+	}
+	for _, tc := range tests {
+		tokens, err := tokenize(tc.input)
+		if err != nil || len(tokens) != 1 {
+			t.Errorf("tokenize(%q) = %+v, %v", tc.input, tokens, err)
+			continue
+		}
+		if tokens[0].pattern != tc.pattern || tokens[0].glob != tc.glob {
+			t.Errorf("tokenize(%q): pattern %q, glob %v; want %q, %v",
+				tc.input, tokens[0].pattern, tokens[0].glob, tc.pattern, tc.glob)
+		}
+	}
+}
+
+func TestExpandGlob(t *testing.T) {
+	origDir, _ := os.Getwd()
+	defer os.Chdir(origDir)
+	dir := t.TempDir()
+	os.Chdir(dir)
+	for _, d := range []string{"sub/deep", "other"} {
+		os.MkdirAll(d, 0755)
+	}
+	for _, f := range []string{"a.go", "b.go", "c.txt", ".hidden.go", "with space.go", "[x].go", "sub/s1.go", "sub/deep/d.go", "other/o.go"} {
+		os.WriteFile(f, nil, 0644)
+	}
+
+	tests := []struct {
+		pattern string
+		want    []string
+	}{
+		{"*.go", []string{"[x].go", "a.go", "b.go", "with space.go"}},
+		{".*.go", []string{".hidden.go"}},
+		{"?.go", []string{"a.go", "b.go"}},
+		{"[ab].go", []string{"a.go", "b.go"}},
+		{"[^a].go", []string{"b.go"}},
+		{"*/*.go", []string{"other/o.go", "sub/s1.go"}},
+		{"*/", []string{"other/", "sub/"}},
+		{"sub/*/*.go", []string{"sub/deep/d.go"}},
+		{"./c*", []string{"./c.txt"}},
+		{dir + "/c*", []string{dir + "/c.txt"}},
+		{`\[x\].go`, []string{"[x].go"}},
+		{"*.xyz", nil},
+		{"[", nil},
+	}
+	for _, tc := range tests {
+		if got := expandGlob(tc.pattern); !reflect.DeepEqual(got, tc.want) {
+			t.Errorf("expandGlob(%q) = %q, want %q", tc.pattern, got, tc.want)
+		}
+	}
+}
+
+func TestExecInput_Wildcards(t *testing.T) {
+	origDir, _ := os.Getwd()
+	defer os.Chdir(origDir)
+	dir := t.TempDir()
+	os.Chdir(dir)
+	for _, f := range []string{"a.go", "b.go", "c.txt"} {
+		os.WriteFile(f, []byte(f+"\n"), 0644)
+	}
+
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"echo *.go > out", "a.go b.go\n"},
+		{"cat *.go > out", "a.go\nb.go\n"},
+		// No match: the word is passed on unchanged, like in sh
+		{"echo *.xyz > out", "*.xyz\n"},
+		{`echo "*.go" '?.go' \*.go > out`, "*.go ?.go *.go\n"},
+		// A redirection to a pattern with a single match uses that file
+		{"echo hi > *.txt; cat c.txt > out", "hi\n"},
+	}
+	for _, tc := range tests {
+		if err := execInput(tc.input); err != nil {
+			t.Errorf("execInput(%q) returned error: %v", tc.input, err)
+		}
+		if got, _ := os.ReadFile("out"); string(got) != tc.want {
+			t.Errorf("%q: got %q, want %q", tc.input, got, tc.want)
+		}
+	}
+
+	err := execInput("echo hi > *.go")
+	if err == nil || err.Error() != "*.go: ambiguous redirect" {
+		t.Errorf("expected ambiguous redirect error, got %v", err)
+	}
+}
+
+func TestStartupFiles(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	sys := sysConfDir
+
+	tests := []struct {
+		login, interactive bool
+		want               []string
+	}{
+		{false, false, nil},
+		{true, false, []string{sys + "/profile", home + "/.gosh_profile"}},
+		{false, true, []string{sys + "/goshrc", home + "/.goshrc"}},
+		{true, true, []string{sys + "/profile", home + "/.gosh_profile", sys + "/goshrc", home + "/.goshrc"}},
+	}
+	for _, tc := range tests {
+		if got := startupFiles(tc.login, tc.interactive); !reflect.DeepEqual(got, tc.want) {
+			t.Errorf("startupFiles(%v, %v) = %q, want %q", tc.login, tc.interactive, got, tc.want)
+		}
+	}
+}
+
+func TestRun_LoginReadsProfile(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	os.Unsetenv("GOSH_TEST_PROFILE")
+	defer os.Unsetenv("GOSH_TEST_PROFILE")
+	os.WriteFile(filepath.Join(home, ".gosh_profile"), []byte("export GOSH_TEST_PROFILE=yes\n"), 0644)
+	// .goshrc is only read by interactive shells
+	os.WriteFile(filepath.Join(home, ".goshrc"), []byte("exit 99\n"), 0644)
+
+	check := `sh -c 'test "$GOSH_TEST_PROFILE" = yes'`
+	if got := run([]string{"-c", check}); got != 1 {
+		t.Errorf("non-login shell: status %d, want 1 (profile must not be read)", got)
+	}
+	if got := run([]string{"-l", "--noprofile", "-c", check}); got != 1 {
+		t.Errorf("--noprofile: status %d, want 1 (profile must not be read)", got)
+	}
+	if got := run([]string{"-l", "-c", check}); got != 0 {
+		t.Errorf("login shell: status %d, want 0 (profile must be read)", got)
+	}
+}
+
+func TestShell_InteractiveReadsRC(t *testing.T) {
+	bin := buildShell(t)
+	home := t.TempDir()
+	os.WriteFile(filepath.Join(home, ".goshrc"), []byte("export GOSH_TEST_RC=from-rc\n"), 0644)
+	os.WriteFile(filepath.Join(home, ".gosh_profile"), []byte("export GOSH_TEST_PROFILE=from-profile\n"), 0644)
+
+	tests := []struct {
+		args []string
+		want string
+	}{
+		{[]string{"-i"}, "from-rc -\n"},
+		{[]string{"-i", "--norc"}, "- -\n"},
+		{[]string{"-i", "-l"}, "from-rc from-profile\n"},
+		{[]string{"-i", "-l", "--norc", "--noprofile"}, "- -\n"},
+	}
+	for _, tc := range tests {
+		cmd := exec.Command(bin, tc.args...)
+		cmd.Env = append(os.Environ(), "HOME="+home)
+		cmd.Stdin = strings.NewReader("echo ${GOSH_TEST_RC:--} ${GOSH_TEST_PROFILE:--}\nexit\n")
+		out, err := cmd.Output()
+		if err != nil {
+			t.Fatalf("%v: %v", tc.args, err)
+		}
+		if !strings.HasSuffix(string(out), tc.want) {
+			t.Errorf("%v: output %q, want suffix %q", tc.args, out, tc.want)
+		}
+	}
+}
+
+func TestExecInput_Source(t *testing.T) {
+	dir := t.TempDir()
+	os.Unsetenv("GOSH_TEST_SOURCE")
+	defer os.Unsetenv("GOSH_TEST_SOURCE")
+
+	file := filepath.Join(dir, "vars")
+	os.WriteFile(file, []byte("# comment\nexport GOSH_TEST_SOURCE=hello\nsh -c 'exit 4'\n"), 0644)
+
+	for _, cmd := range []string{"source", "."} {
+		os.Unsetenv("GOSH_TEST_SOURCE")
+		execInput(cmd + " " + file)
+		if os.Getenv("GOSH_TEST_SOURCE") != "hello" {
+			t.Errorf("%s: variable was not set in the current shell", cmd)
+		}
+		if lastStatus != 4 {
+			t.Errorf("%s: $? = %d, want 4 (status of the last command)", cmd, lastStatus)
+		}
+	}
+
+	err := execInput("source " + filepath.Join(dir, "missing"))
+	if err == nil || !strings.Contains(err.Error(), "source: "+dir+"/missing: no such file or directory") {
+		t.Errorf("unexpected error for missing file: %v", err)
+	}
+	if lastStatus != 1 {
+		t.Errorf("$? = %d for missing file, want 1", lastStatus)
+	}
+
+	// A file that sources itself is stopped
+	loop := filepath.Join(dir, "loop")
+	os.WriteFile(loop, []byte("source "+loop+"\n"), 0644)
+	if err := execInput("source " + loop); err == nil {
+		t.Error("expected an error for a file that sources itself")
+	}
+}
+
+func TestGetHomeDir_UsesHOME(t *testing.T) {
+	t.Setenv("HOME", "/gosh/test/home")
+	if got := getHomeDir(); got != "/gosh/test/home" {
+		t.Errorf("getHomeDir() = %q, want $HOME", got)
+	}
+	if words, _ := splitWords("echo ~/x"); words[1] != "/gosh/test/home/x" {
+		t.Errorf("~/x = %q, want it based on $HOME", words[1])
+	}
+
+	// Without $HOME the user database is used
+	t.Setenv("HOME", "")
+	if got := getHomeDir(); got == "" {
+		t.Error("getHomeDir() is empty without $HOME")
+	}
+}
+
+func TestExecInput_Background(t *testing.T) {
+	origDir, _ := os.Getwd()
+	defer os.Chdir(origDir)
+	dir := t.TempDir()
+	os.Chdir(dir)
+
+	// The shell does not wait for a background job, wait does
+	start := time.Now()
+	if err := execInput("sh -c 'sleep 0.3; echo done > out' &"); err != nil {
+		t.Fatal(err)
+	}
+	if lastStatus != 0 {
+		t.Errorf("$? = %d after starting a background job, want 0", lastStatus)
+	}
+	if time.Since(start) > 200*time.Millisecond {
+		t.Error("the shell waited for the background job")
+	}
+	if _, err := os.Stat("out"); err == nil {
+		t.Error("background job finished too early")
+	}
+	if err := execInput("wait"); err != nil {
+		t.Fatal(err)
+	}
+	if got, _ := os.ReadFile("out"); string(got) != "done\n" {
+		t.Errorf("out = %q after wait", got)
+	}
+	if len(jobTable) != 0 {
+		t.Errorf("job table not empty after wait: %d jobs", len(jobTable))
+	}
+
+	// wait %n returns the status of the job
+	execInput("sh -c 'exit 3' &")
+	execInput("wait %1")
+	if lastStatus != 3 {
+		t.Errorf("$? = %d after wait %%1, want 3", lastStatus)
+	}
+
+	// Without job control, background jobs read from /dev/null
+	execInput("cat > stdin.txt &")
+	execInput("wait")
+	if got, err := os.ReadFile("stdin.txt"); err != nil || len(got) != 0 {
+		t.Errorf("background job read %q, %v from stdin", got, err)
+	}
+
+	// jobs lists running jobs, also into a redirection
+	execInput("sleep 0.3 &")
+	execInput("jobs > jobs.txt")
+	if got, _ := os.ReadFile("jobs.txt"); !strings.Contains(string(got), "Running                 sleep 0.3 &") {
+		t.Errorf("jobs output = %q", got)
+	}
+	execInput("wait")
+
+	// Builtins that change the shell cannot run in the background
+	if err := execInput("cd / &"); err != nil {
+		t.Fatal(err)
+	}
+	execInput("wait %1")
+	if wd, _ := os.Getwd(); wd != dir {
+		t.Errorf("cd in the background changed the directory to %s", wd)
+	}
+
+	// fg and bg need job control
+	for _, cmd := range []string{"fg", "bg"} {
+		if err := execInput(cmd); err == nil || err.Error() != cmd+": no job control" {
+			t.Errorf("%s without job control: %v", cmd, err)
+		}
+	}
+	if err := execInput("wait %9"); err == nil || err.Error() != "wait: %9: no such job" {
+		t.Errorf("wait %%9: %v", err)
+	}
+}