> but they mean “any character between the character ‘a’ and the character ‘z’”, which happens to correspond to the lower case letters in English
‘Only’ in the most commonly used character encodings. In EBCDIC (https://en.wikipedia.org/wiki/EBCDIC), the [a-z] range includes more than 26 characters.
That’s one of the reasons POSIX has character classes (https://en.wikipedia.org/wiki/Regular_expression#Character_c...). [:lower:] always gets you the lowercase characters in the encoding that the program uses.
