Convert admin users to standard user, except admin account specified

adminConvert.sh

#!/bin/sh

## Demote admin users to standard
##
## author unknown
## Get list of users for demotion
## 
#In the above, you need to replace the reverse grep (grep -ve) with your local admin #accounts between the quote marks. Place a pipe betwen each name if you have multiple #ones. if you only have one, no need for "-ve", just use grep -v "youradminname"

/bin/echo "Building list of local user accounts for demotion"
userList=$( /usr/bin/dscl . -list /Users UniqueID | /usr/bin/awk '$2 >= 501 { print $1; }' | /usr/bin/grep -v “youradminaccountgoeshere” )

## Remove admin privs from each user and add them into the _lpadmin group
for i in $userList; do
	if [[ `/usr/sbin/dseditgroup -o checkmember -m $i admin | /usr/bin/awk '{ print $1 }'` = "yes" ]]; then
	/bin/echo "User $i is currently an admin. Converting into Standard User"
	/usr/sbin/dseditgroup -o edit -d $i -t user admin
	/bin/echo "Adding $i into _lpadmin group"
	/usr/sbin/dseditgroup -o edit -a $i -t user _lpadmin
		else
			echo "User $i is currently a Standard User. Leaving as is."
	fi
done

I don't remember where I got this script from.... but it works great!!!!