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Using bash variables in awk

While there seems nothing wrong with this:

sign="--"
awk '{if ($1 == $sign ) print $1 }'

..it doesn’t give the intended result. To be able to use bash variables in awk, you first need to assign the variables with the -v option:

sign="--"
awk -v sign="$sign" '{if ($1 == sign ) print $1 }'

From the awk man page:

The option -v followed by var=value is an assignment to be done before (the awk) prog is  executed;  any  number  of  -v  options  may be present.

This entry was posted on Friday, April 21st, 2006 at 10:59 am and is filed under bash, linux, nerdnotes, osx. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

One Response to “Using bash variables in awk”

  1. Marc says:
    June 24, 2006 at 8:03 am

    Good tip. I recall having to use this a while back and it took me a while to find it.

    Though I suspect that when you’re having to do stuff like this, it’s probably a pretty good sign that your shell script is getting too complicated and it should probably be done in something like Perl.