Bash: Pass Shell Variables To awk

How do I pass shell variables to awk command or script under UNIX like operating systems?

The -v option can be used to pass shell variables to awk command. Consider the following simple example,

 
root="/webroot"
echo | awk -v r=$root '{ print "shell root value - " r}'
 

In this example search file using awk as follows:

 
#!/bin/bash
# Usage : Search word using awk for given file.
# Syntax: ./script "word-to-search" fileToSearch
s=$1
i=$2
awk -v search="$s" '$0 ~ search' "$i"
 

Save and close the file. Run it as follows:
$ ./script.sh "vivek" /etc/passwd
Sample outputs:

vivek:x:1000:1000:Vivek Gite,,,:/home/vivek:/bin/bash

Setup shell variables using awk

You can use eval command as follows:

 
eval $(awk 'BEGIN{ print "vech=Bus"}' < /dev/null)
echo $vech
 

Sample outputs:

Bus