Question

2

Simple: check if volume group is found with a if

rated 0 times [ 2] [ 0] / answers: 1 / hits: 5904 / 3 Years ago, mon, may 17, 2021, 12:18:54

I am working on a script to check if volume group vg0 exist. The problem is that it return Found even when I delete the volume group. So very unsure what is wrong.

#!/bin/bash



if vgdisplay | grep 'vg0' | awk '{print $3}'; then

  echo "Found"

else

  echo "Not found"

fi

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itutejagua

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answered 3 Years ago ionash · Accepted Answer

The if condition in this case is evaluated based on the exit code of awk, which is likely to be zero unless one of the previous commands in the pipeline failed to execute.

You could use the -q option for grep instead:

if vgdisplay | grep -q 'vg0'; then

  echo "Found"

else

  echo "Not found"

fi

The same could also be written as:

vgdisplay | grep -q 'vg0' && echo "Found" || echo "Not found"