How can i use awk/Grep to search a specified column for a variable

Question

I have data like the following:

apple pear sugar pizza
pizza chicken pasta turkey

I want to grep for "pizza" but only grep the fourth column. I know i can use:

awk '$4 == "pizza"'

However i have a variable named food which contains the word pizza. When i do

food=pizza
awk '$4 == "$food"'

I receive an error and also when i change to double apostrophes i receive this error:

awk: line 1: syntax error at or near ==

how can i achieve this?

jesse_b · Accepted Answer · 2019-09-14T20:26:36.770

0

Your shell variable won't expand inside the single quotes used for the awk program.

You can pass a shell variable to awk using the -v option:

food=pizza
awk -v food="$food" '$4 == food'

edited Sep 14 '19 at 20:26

answered Sep 14 '19 at 20:20

jesse_b

This does not work:. echo cake cake cake pizza | awk -v pizza="$food" '$4 == food' – thomas Sep 14 '19 at 20:24
can you show example where food variable is set to pizza? – thomas Sep 14 '19 at 20:25
@thomas: It's no different than what you did in your question but I've added it – jesse_b Sep 14 '19 at 20:26

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