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?"

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

up vote 4 down vote accepted

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

answered May 11 '12 at 16:37

kopischke
1563

eepp · Answer 2 · 2012-05-11 18:44:03Z

up vote 3 down vote

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

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

answered May 11 '12 at 18:44

eepp
311

3

You can also use grep -q then you don't need &>/dev/null. – Mikel May 11 '12 at 19:53

2 Answers