- a{b,c}d, nested braces, empty alternatives (file{,.bak})
- sequences {1..5}, {5..1}, {1..10..3}, zero-padded {01..10}, letters
{a..e}
- happens first on the command text, the results go through ~,
variable and wildcard expansion
- quoted/escaped braces, ${...} and braces without comma or valid
sequence are kept; \, protects a comma
- a redirection target must expand to one word (ambiguous redirect),
a word may expand to at most 100000 words
- completion escapes { in file names
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>