1 1 11.7 Shell Pattern Matching 1 =========================== 1 1 Nowadays portable patterns can use negated character classes like 1 `[!-aeiou]'. The older syntax `[^-aeiou]' is supported by some shells 1 but not others; hence portable scripts should never use `^' as the 1 first character of a bracket pattern. 1 1 Outside the C locale, patterns like `[a-z]' are problematic since 1 they may match characters that are not lower-case letters. 1