- ${#v}, ${v#p} ${v##p} ${v%p} ${v%%p}, ${v/p/r} ${v//p/r} ${v/#p/r}
${v/%p/r}, ${v:off:len}, ${v-w} ${v:=w} ${v:+w} ${v:?msg}; nested ${}
- arithmetic expansion $((...)) with the C operators, ** and assignments
- set -e, set -x, set -o pipefail (also as gosh options, passed on to
subshells); set shows variables, set -o the options
- trap for EXIT and signals; scripts with an EXIT trap run it on
SIGINT/SIGTERM/SIGHUP too
- eval, exec (also exec > file without a command), $!, wait pid
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- functions: name() { ...; }, function name { ...; }, return, local,
unset -f; in pipes, & and $(...) they run in a subshell that gets all
function definitions and the positional parameters
- positional parameters $0, $1 ... ${10}, $#, "$@", "$*", $$; set by
gosh script args, gosh -c command name args, function calls,
source file args and set --; shift; for x without "in"
- case word in pattern|pattern) ...;; esac and { list; } groups
- read [-r] [-p prompt] [name ...] with $IFS splitting and $REPLY
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- $(command) is replaced by the output of command, which runs in a
subshell (gosh -c), so cd/set in it do not change the shell
- trailing newlines are removed; unquoted the output is split into words
at blanks and newlines, "$(...)" stays one word; wildcards in the
output are not expanded
- nested substitutions, quotes and operators inside are handled; the
list, alias and brace scanners skip $(...) as a whole
- a command that consists only of a substitution has its exit status,
Ctrl+C in a substitution aborts the command
- $((...)) is reported as not supported
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Florian WaltherandClaude Opus 5.5