The ‘-regex’ and ‘-iregex’ tests of
matching by regular expression, as does the ‘--regex’ option of
Your locale configuration affects how regular expressions are interpreted. See Environment Variables, for a description of how your locale setup affects the interpretation of regular expressions.
There are also several different types of regular expression, and
these are interpreted differently. Normally, the type of regular
expression used by
locate is the same as is
used in GNU Emacs. Both programs provide an option which allows you
to select an alternative regular expression syntax; for
this is the ‘-regextype’ option, and for
locate this is
the ‘--regextype’ option.
These options take a single argument, which indicates the specific regular expression syntax and behaviour that should be used. This should be one of the following: