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How can I count the number of lines matching a pattern returned from a linux command

I want the number of lines returned beginning with 'foo' , so if I pipe the output to grep will this work?

cat | grep -c ^foo
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  • 1
    Why do you even ask, if you answered the question by yourself. Or simply check with your next nearest shell.
    – Roman
    Feb 19, 2013 at 12:36
  • 3
    Because there may be a better way
    – Dave
    Feb 19, 2013 at 13:08
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    Useless use of cat. grep -c pattern file. Yes it's not that much but as soon as you run that thru a loop that runs a couple of thousand times you'll want to save on forks Feb 19, 2013 at 13:17
  • Then you could instead ask for alternate ways. Also Server Horror's comment should be an answer.
    – Alex Hall
    Dec 14, 2017 at 0:05

3 Answers 3

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cat | grep ^foo | wc -l

TO show how many lines containing foo are there.

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Per Server Horror's comment:

grep -c pattern file

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From grep man page:

****General Output Control****

    -c, --count      Suppress normal output;

instead print a count of matching lines for each input file. With the -v, --invert-match option (see below), count non-matching lines. (-c is specified by POSIX.)

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