如何使用 grep 进行匹配但不打印匹配项？

Question

I'm new to linux shell and am trying to do this, preferably in one line, with the following condition: It can't output anything to the terminal.

/var/folder/program.exe -L parameters | grep text_to_filter && echo SomeText >'/tmp/Log.txt'

The problem is the.exe spits out XML data to terminal. I can't figure out how to grep, use the exit status, but not have the screen cluttered with the output of each match. If I use /dev/null 2>&1 , it pipes it quite but then I can't grep the data. Any idea's?

Answer 1

Use grep -q (quiet)

/var/folder/program.exe -L parameters |
grep -q "text_to_filter" && echo 'SomeText' > '/tmp/Log.txt'

As per man grep :

-q, --quiet, --silent Quiet; do not write anything to standard output. Exit immediately with zero status if any match is found, even if an error was detected. Also see the -s or --no-messages option.

Answer 2

Try using |& rather than just |. (needs bash 4)