bash config files

For this task, you don't have to write fat parser routines (unless you want it 100% secure or you want a special file syntax) - you can use Bash's source command. The file to be sourced should be formated in key="value" format, otherwise bash will try to interpret commands:

#!/bin/bash
echo "Reading config...." >&2
source /etc/cool.cfg
echo "Config for the username: $cool_username" >&2
echo "Config for the target host: $cool_host" >&2

So, where do these variables come from? If everything works fine, they are defined in /etc/cool.cfg which is a file that's sourced into the current script or shell. Note that this is not the same as executing this file as a script! The sourced file most likely contains something like:

cool_username="guest"
cool_host="foo.example.com"

These are normal statements understood by Bash, nothing special to do. Of course (and that is a big disadvantage under normal circumstances) the sourced file can contain everything that Bash understands, including evil code!
Src/more: http://wiki.bash-hackers.org/howto/conffile