Linux Shell Scripting Cookbook - Third Edition

How to do it...

Let's go through another example usage of IFS to parse the /etc/passwd file. In the /etc/passwd file, every line contains items delimited by :. Each line in the file corresponds to an attribute related to a user.

Consider the input: root:x:0:0:root:/root:/bin/bash. The last entry on each line specifies the default shell for the user.

Print users and their default shells using the IFS hack:

#!/bin/bash 
#Desc: Illustration of IFS 
line="root:x:0:0:root:/root:/bin/bash"  
oldIFS=$IFS; 
IFS=":" 
count=0 
for item in $line; 
do 

     [ $count -eq 0 ]  && user=$item; 
     [ $count -eq 6 ]  && shell=$item; 
    let count++ 
done; 
IFS=$oldIFS 
echo $user's shell is $shell;

The output will be as follows:

root's shell is /bin/bash

Loops are very useful in ...