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Re: remove lines matching list of strings

by TomDLux (Vicar)
on Nov 08, 2012 at 21:51 UTC ( #1002996=note: print w/ replies, xml ) Need Help??


in reply to remove lines matching list of strings

grep -v -F -f file2 file1

English translation: using the Unix grep command, search file1 for lines which do not match ( -v ) the fixed strings ( -F ) ( as opposed to regular expressions ) found in file2 ( -f file2 ).

There are versions of grep available for Windows. Mac OS has a Unix basis, so it already has it.

If you absolutely have to do it in Perl, I would use the lines from file2 as the keys of a hash, assigning the number 1 as a value. Then, as I read the other file, it's trivial to check whether it is present in the hash.

As Occam said: Entia non sunt multiplicanda praeter necessitatem.


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Re^2: remove lines matching list of strings
by rootcho (Pilgrim) on Nov 08, 2012 at 22:51 UTC
    Yes, I was thinking in the same line... if done in perl using hash seem to be better than building giant regex.
    Heh...didn't know about -F option.. will check it out
    thanks

      Neither did I, but I scanned through man grep to make sure I was doing things right. I did have a vague recollection there was an option to search for strings rather than regex ... it helps if you know to search for something.

      As Occam said: Entia non sunt multiplicanda praeter necessitatem.

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