Parsing In Shell Script

January 22, 2019

Here a small snippet to parse name:value pairs is shell script:

#!/bin/sh

values="

centos: CentOS 7
ubuntu:    Ubuntu 1804    

"

IFS=$'\n'
for i in $values; do
    IFS=':' read -ra vals <<< "$i"	
    unset IFS
    read  -rd '' name <<< "${vals[0]}"
    read  -rd '' value <<< "${vals[1]}"
    echo "[$name] = [$value]"
done

Output:

[centos] = [CentOS 7]
[ubuntu] = [Ubuntu 1804]

It mainly utilize the “internal field separator” or IFS, and the read builtin function.

The first step is to split the string using new line, with IFS=$'\n'.

Then we split using the colon :, and use read -ra vals to split the input and put it in an array.

Finally, we use read -rd '' again to get trim spaces from each field.