I have to write a rbac script to add something into a role's profile, this script will be executed for many times, during this script, it will add a block into the profile.
if the profile exists, it should check the block has been there, if, just replace it with the latest settings, take an example here:
if [ -r /it/etc/envinit ]; then
. /it/etc/envinit
fi
The block upon should be added into the profile, customer may modify this profile, it must be a strict check that there is no duplicate lines like that settings. How should I do to check that ?

what if there is a blank line or comment line added by customer among that block? what if some spaces added into the lines different as the original?
Can anyone give me some sugguestion?
Thanks a lot.