GHX Manual

Using POSIX extended regular expressions

POSIX extended regular expressions (PERE) is a way to describe string using wildcards and pattern. The following description doesn't provide a full description of PERE but just intend to help you at the beginning.

the following rules are available:

a\|b	search for a or b
ab	search for the symbol a followed by symbol b
.	this symbol match any other.
a*	symbol a from 0 upto unlimited times.
[abc]	search for a or b or c
[a-z]	search for symbol between a (included) and z (included).
[^a-z]	search for symbol not between a (included) and z (included).
(abc) or abc	word abc
^abc	search for line beginning by the word abc.
abc$	search for line ending by the word abc.

You can mix these rules as you need.

Here is some samples:

(toto|titi): match any line containing word toto or word titi.
^A[c-t]*O: find line beginning by an A followed by 0 or more letters between c and t and followed by an O.
'AkcO', 'AO', 'AdgztrhgtrhthdsfhO' matches this pattern.
'A O', 'AbO', 'Acdef' doesn't.
^A(toto|titi)*.B*O$: find line beginning by an A followed by 0 or more word toto or titi followed by 1 undefined character followed by 0 or more letter B and ending by an O.
'A O', 'Atototototiti BBBBBBBO' matches this pattern.
'A Ok', 'BO' doesn't.