Shell Programming and Scripting

hi anyone
how can use grep with wildcard. for example grep "sample?txt" filename doesn't show sample1txt or grep "sample*txt" filename doesn't show sample123.txt that there is in filename.





many thanks
samad

grep uses regexes, not globs, with slightly different meanings. In glob, * means 'zero or more characters', in regex, it means 'zero or more of the previous character'.

So something* in regex terms would match something, somethingg, somethingggggggggggggggggggggg, somethin, but not somethina.

In regex, ? means "zero or one of the previous character" while . means "any character". You can combine the two as .? to mean "zero or one of any character" for example.

So try grep 'sample.txt' to match sampleatxt, samplebtxt, samplectxt, etc.

Thanks
so, What is the way to find the following words in grep:
e.g: sample123.txt sampleahgdtxt

With regards to post #1, that would be:

Code:

sample.txt

and

Code:

sample.*txt

respectively

Hmm - it would match "somethina" unless terminated by e.g. line end $ or something else...

Yes it would match the somethin in somethina.
Often you can improve that with grep -w (word match), then somethina or somethinga or sample.txta or asample.txt would not match.

That will work only if your grep is a non-POSIX grep, because this is a (GNU, i believe) non-standard extension (see here).

bakunin