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I often find myself searching through a bunch of code using grep in order to pin down what I'm looking for. Sometimes I get a list of files a little longer than I hoped. At this point I want to perform a second grep, but only searching through the files returned by the first grep search. Is there a way to do this? I basically want to cross-reference two grep searches and only get back the files with both results contained within them.

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grep -lZ "first string" * | xargs -0 grep -l "second string"

  • First grep will return the files containing first string.

  • Second grep will do the same for second string, but over the results from the first grep.

  • The -Z argument to grep and the -0 argument to xargs work together to enable support for filenames that include spaces.

Edit - thanks to Ajedi32:

xargs lets you use the results from a command as the arguments to another.

From the xargs's Wikipedia article, xargs is a command on Unix and most Unix-like operating systems used to build and execute command lines from standard input.

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  • Awesome thank you. Can you enlighten me as to what xargs is? Commented Aug 4, 2014 at 17:26
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    @AlexFord - from the xarg's Wikipedia article, xargs is a command on Unix and most Unix-like operating systems used to build and execute command lines from standard input.. In other words, it allows you to use the results from a command as the standard input to another. Try to use the same commands but without xargs, and you will see the problem (grep -l "first string" * | grep -l "second string") Commented Aug 4, 2014 at 17:35
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    @ntoskrnl - you will get a "(standard input)" message. A good explanation is this one, from Joseph R. Commented Aug 4, 2014 at 20:01
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    @jim "it allows you to use the results from a command as the standard input to another" No, that's what piping does. xargs lets you use the results from a command as the arguments to another. Commented Aug 4, 2014 at 20:04
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    @Ajedi32 - you are correct - my bad. Edited answer :-) Thanks! Commented Aug 4, 2014 at 20:11

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