HP 3000 Manuals

System Debug Reference Manual

Character Classes (Match Any One of the Following Characters) 

The metacharacter "[" signals that the characters following, up to the
next "]", form a character class, that is, a regular expression that
matches any single character from the bracketed list.  The character
class "[aA]" matches "a" or "A".  A dash "-" is used to signify a range
of characters in the ASCII collating sequence.  For example, "[a-zA-Z]"
matches any alphabetic character, while "[0-9]" matches any numeric
character.  If the first character in a character class is an "^", then
any character not in the class constitutes a match; for example, [^a]
matches any character except an "a".

MPE/iX 5.0 Documentation