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Re: grep '-o' ???
From: |
Benno Schulenberg |
Subject: |
Re: grep '-o' ??? |
Date: |
Thu, 01 Nov 2007 11:51:04 +0100 |
User-agent: |
KMail/1.9.7 |
Leslie E. Ballentine wrote:
> >address@hidden ~]% cat testfile
> >12345
> > -o sss
> >-o
> >
> >address@hidden ~]% grep 'o' testfile
> > -o sss
> >-o
> >address@hidden ~]% grep '-o' testfile
>
> At this point, grep hangs indefinitely.
> It seems that grep cannot find the string '-o'.
It is waiting for input, because it interprets '-o' as the
option -o, and thus sees testfile as a pattern.
> And how do I search a file for the characters "-o"?
Precede it with the option -e.
$ grep -e -o testfile
Or quote plus escape the dash:
$ grep '\-o' testfile
Just quoting the pattern is not enough, because anything can be
quoted, for example:
$ 'grep' '-e' 'hmm' '-e' '-o' 'testfile'
Benno