Running a command based on output of previous command

Question

Consider the following command. I want to echo "yes" if grep has output and echo "no" if grep returns no output.

cat myfile | grep "something"

Can I do this without if command?

Aside from the useless use of cat, what exactly is your problem with if? Or maybe the correct question is "what are you really trying to do?" — geekosaur, Commented May 11, 2012 at 16:30

kopischke · Accepted Answer · 2012-05-11 16:37:34Z

5

[[ -n $(your command) ]] && echo "yes" || echo "no"

answered May 11, 2012 at 16:37

kopischke

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eepp · Accepted Answer · 2012-05-11 18:44:03Z

5

grep sets its exit code to 0 ("success") if it finds something:

grep something myfile &>/dev/null && echo yes || echo no

answered May 11, 2012 at 18:44

eepp

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You can also use grep -q then you don't need &>/dev/null.
– Mikel
Commented May 11, 2012 at 19:53

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2 Answers 2