CODEWITHSUNDEEP
unixawk
speciousfool
speciousfool

Reputation: 2660

How to print the Nth column of a text file with AWK using argv

Suppose I have a text file with data separated by whitespace into columns. I want to write a shell script which takes as input a filename and a number N and prints out only that column. With awk I can do the following:

awk < /tmp/in '{print $2}' > /tmp/out

This code prints out the second column.

But how would one wrap that in a shell script so that a arbitrary column could be passed in argv?

Upvotes: 37

Views: 87566

Answers (2)

Ray
Ray

Reputation: 2258

awk -v x=2 '{print $x}'

or in a shell script:

#!/bin/sh
num=$1
awk < /tmp/in -v x=$num '{print $x}' > /tmp/out

Upvotes: 47

strager
strager

Reputation: 90072

awk '{print $'$myvar'}' < /tmp/in > /tmp/out

Where $myvar is your variable column (an integer). Watch out for script injections!

Upvotes: 7

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