Gordon Messmer <[EMAIL PROTECTED]> writes: > On Fri, 2002-04-19 at 14:16, Harry Putnam wrote: >> >> I'm not really sure what constitutes a posix legal regex but I don't >> think it includes trick riders like having to match a specific part >> of a string, unless put into the regex itself with anchors or the >> like. > > A regex is a regex, but a regex search is not a regex match. I don't
Not exactly. There are several common sets of regex rules. The one in find is not as powerfull as what I called the `POSIX' set. > know that Perl provides both, and if it does I don't recall how they're > differentiated. Other applications do. Python, for instance > differentiates them thusly: > http://www.python.org/doc/current/lib/matching-searching.html > > Find requires a "match" like Python's, rather than a "search" like perl > or grep. Now, I may have used the wrong term (POSIX) and still do not really know what constitutes a posix legal regex. However the notation used with find is weaker in several ways (As I mentioned in my 1st post in this thread) than what I referred to as POSIX. In the context of the original post, the comparison was to perl regex. The usage in find would better be described as regex-like. Since it is weaker in several ways, and lacks some of the more powerfull syntax. It is a nice addition none-the-less. I only said it isn't the real mcCoy. Far as I know there is no stipulation on a regex to match in any special way. Making that stipulation has already weakened the regex engine involved. egrep awk and perl all would give a different (more versatile) result than that used in find. Limiting the match in some way only being the first. For example: touch aardvark find . -regex 'a+ardvark' nothing Whereas ls|egrep 'a+rdvark' aardvark works or find . -regex 'a*rdvark' nothing whereas ls |egrep 'a*rdvark' aardvark Using a*rdvark with find -regex fails but with posix regex it is another way to find something like aardvark Or find . -regex '\(a\)\1rdvark' nothing or find . -regex '(a)\1rdvark' find: Invalid back reference Whereas ls |egrep '(a)\1rdvark' aardvark There are more examples. But my only point here was that full regex is more powerfull because it is more versatile. Not that the usage in find is a bad thinkg. The perl script I submitted (barring any scripting errors) would be more versatile as a result. _______________________________________________ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
