CODE EXAMPLE FOR SHELL

bash if user exists in a group then add

#!/bin/bash
# init
USERID="$1"
#....
/bin/egrep  -i "^${USERID}:" /etc/passwd
if [ $? -eq 0 ]; then
   echo "User $USERID exists in /etc/passwd"
else 
   echo "User $USERID does not exists in /etc/passwd"
fi
# ....