Well, sudo is a great tool for delegating permissions among admins. But, it's really hard to find a great tool which would give an interactive way of editing /etc/sudoers file. Now, when I say "editing", I really refer to add new groups, users, aliases in the /etc/sudoers file. visudo is great tool, but again, we gotta edit the raw sudoers file. So, I was thinking of having some kind of a script which would simply prompt me what to enter and the script will take care of rest of the things like how to enter that information in the sudoers file.
So, here I want to share my work. It's not really a robust script. There is a lot of things to be implemented (details are mentioned in the script itself) yet.
So script gurus, grab the code, test it on different *nixes, modify it, play with it, and make it better. And yes, don't forget to distribute the code 
===========
addsudoers.sh
#! /bin/bash
# ============================================================================
# This script securely and accurately adds users into the /etc/sudoers file
# It's for those who don't have the fancy GUI to add users in sudoers list
# or simply do not want to use a GUI (like me ;-D)
# Created by Admin_XOR; however, anyone is free to modify and re-distribute it
# Thanks to the indepth manual on /etc/sudoers available at:
# http://www.gratisoft.us/sudo/sudoers.man.html
# ============================================================================
## I guess I'm only a half way of entire implementation of sudoers file
## Things that I haven't implemented yet are:
## NOPASSWD, run as a group like (: wheel), changing deafult values, and
## the rest is waiting to be figured out by you folks ;-)
## check if the user executing the script has an effective user id 0
if [ "$EUID" -ne 0 ]; then
echo "ERROR: You should be root or your EUID should be 0"
exit 1
fi
## check if there's /etc/sudoers.tmp file; this is created by visudo
## if it's there, we will not execute the script as someone might be accessing
## sudoers file
## *** WARNING *** uncomment the next line at your own risk :-P
#sudoers=/etc/sudoers
## just for testing: a fake sudoers file
sudoers=~/sudoers
## we dont need to check if sudoers file exists; do we??
if [ -f "$sudoers.tmp" ]; then
echo "ERROR: sudoers file is in use"
## gives a hint who might be using it
/sbin/fuser -u $sudoers
exit 2
else
# create a fake lock file recognizable by visudo
# this will prevent visudo from opening sudoers while we are working
touch $sudoers.tmp
fi
## we should keep a backup of the original sudoers file with appropriate
## timestamp even before we access the file and make any changes to it
tstmp=$( date +%F-%H-%M-%S )
cp $sudoers $sudoers.$tstmp.bak
## now, we are good to go ahead and do the changes in sudoers
## important global vairiables
## some of them have not been used. But, I'm half way to implement full
## features of sudoers file. So, who knows!! I may need them tomorrow ;-)
usr_name=""
grp_name=""
sys_name=""
rusr_name=""
rgrp_name=""
cmd_name=""
## here we define the functions
## writes the users specification part in the sudoers file in the form of
## USER_OR_GROUP SYSTEM = (RUNAS_USER_OR_GROUP) COMMANDS
function func_write {
echo "# =================" >>$sudoers
me=$( logname )
d=$( date +%F )
t=$( date +%T )
echo -n "Write the changes? [y/n]: "
read ans
if [ "$ans" == "n" ] || [ "$ans" == "N" ]; then
return
else
echo "# modified by $me on $d at $t" >>$sudoers
tmp="$1 $2 = ($3) $4"
echo $tmp >>$sudoers
fi
}
## writes the aliases created
function func_commit {
echo "# =================" >>$sudoers
me=$( logname )
d=$( date +%F )
t=$( date +%T )
echo -n "Write the changes? [y/n]: "
read ans
if [ "$ans" == "n" ] || [ "$ans" == "N" ]; then
return
else
echo "# modified by $me on $d at $t" >>$sudoers
tmp="$1 $2 = $3"
echo $tmp >>$sudoers
fi
}
## this function gets existing alias names for a specified alias type
## from sudoers
function func_get_alias_name {
ali=$1
echo "Existing $ali is(are): "
grep ^$ali $sudoers | cut -d " " -f 2 -
}
## takes the user name
function func_user {
echo -n "Enter a valid user name: "
read usr
if [ "$usr" == "" ]; then
echo "User name cannot be empty"
return
fi
usr_name=$usr
}
## takes the group name
function func_group {
echo -n "Enter a valid group name: "
read grp
if [ "$grp" == "" ]; then
echo "Group name cannot be empty"
return
fi
grp_name=%$grp
}
## function to take input for aliases or direct entries
function func_input {
nam=$1
plac=""
if [ "$nam" == "h" ]; then
plc="host"
elif [ "$nam" == "r" ]; then
plc="runas user"
elif [ "$nam" == "c" ]; then
plc="command"
else
return
fi
echo
echo "Please select: "
echo "1 Enter $plc name(s) manually"
echo "2 Select from an existing $plc Alias"
echo -n "Enter your choice: "
read choi
mach=ALL
case $choi in
1 )
echo "Enter a $plc name; if more than one, then in comma separated -"
echo -n "format; if empty ALL will be used: "
read sys
if [ "$sys" != "" ]; then
mach=$sys
fi
;;
2 )
if [ "$plc" == "host" ]; then
func_get_alias_name "Host_Alias"
echo -n "Enter your selection from above alias: "
read sys
if [ "$sys" != "" ]; then
mach=$sys
fi
elif [ "$plc" == "runas user" ]; then
func_get_alias_name "Runas_Alias"
echo -n "Enter your selection from above alias: "
read sys
if [ "$sys" != "" ]; then
mach=$sys
fi
elif [ "$plc" == "command" ]; then
func_get_alias_name "Cmnd_Alias"
echo -n "Enter your selection from above alias: "
read sys
if [ "$sys" != "" ]; then
mach=$sys
fi
else
[ ] # do nothing
fi
;;
* )
echo "Error: Incorrect choice" ;;
esac
if [ "$plc" == "host" ]; then
sys_name=$mach
elif [ "$plc" == "runas user" ]; then
rusr_name=$mach
elif [ "$plc" == "command" ]; then
cmd_name=$mach
else
[ ] # do nothing
fi
}
## wrapper function for func_input
function func_mrc {
func_input "h"
func_input "r"
func_input "c"
}
## function to create User_Alias
function func_create_user_alias {
echo -n "Enter user alias name: "
read ali
if [ "$ali" == "" ]; then
echo "User Alias name should not be empty"
return
fi
echo -n "Enter # of users to be added in $ali: "
read num
if [ "$num" == "" ] || [ "$num" -eq 0 ]; then
echo "Number of users should not be empty or 0"
return
fi
usr_list=""
list=$( seq $num )
for i in $list; do
echo -n "Enter user $i: "
read usr
if [ "$i" -eq 1 ]; then
usr_list="$usr"
else
usr_list="$usr_list, $usr"
fi
done
## now, it's time to write this in sudoers file
func_commit "User_Alias" $ali "$usr_list"
}
## this function creates a runas alias
function func_create_runas_alias {
echo -n "Enter runas alias name: "
read ali
if [ "$ali" == "" ]; then
echo "Runas Alias name should not be empty"
return
fi
echo -n "Enter # of users to be added in $ali: "
read num
if [ "$num" == "" ] || [ "$num" -eq 0 ]; then
echo "Number of users should not be empty or 0"
return
fi
usr_list=""
list=$( seq $num )
for i in $list; do
echo -n "Enter user $i: "
read usr
if [ "$i" -eq 1 ]; then
usr_list="$usr"
else
usr_list="$usr_list, $usr"
fi
done
## now, it's time to write this in sudoers file
func_commit "Runas_Alias" $ali "$usr_list"
}
## this function creates a host alias
function func_create_host_alias {
echo -n "Enter host alias name: "
read ali
if [ "$ali" == "" ]; then
echo "Host Alias name should not be empty"
return
fi
echo -n "Enter # of hosts to be added in $ali: "
read num
if [ "$num" == "" ] || [ "$num" -eq 0 ]; then
echo "Number of hosts should not be empty or 0"
return
fi
usr_list=""
list=$( seq $num )
for i in $list; do
echo -n "Enter host $i: "
read usr
if [ "$i" -eq 1 ]; then
usr_list="$usr"
else
usr_list="$usr_list, $usr"
fi
done
## now, it's time to write this in sudoers file
func_commit "Host_Alias" $ali "$usr_list"
}
## this function creates a command alias
function func_create_cmnd_alias {
echo -n "Enter command alias name: "
read ali
if [ "$ali" == "" ]; then
echo "Command Alias name should not be empty"
return
fi
echo -n "Enter # of commands to be added in $ali: "
read num
if [ "$num" == "" ] || [ "$num" -eq 0 ]; then
echo "Number of commands should not be empty or 0"
return
fi
usr_list=""
list=$( seq $num )
for i in $list; do
echo -n "Enter command $i: "
read usr
if [ "$i" -eq 1 ]; then
usr_list="$usr"
else
usr_list="$usr_list, $usr"
fi
done
## now, it's time to write this in sudoers file
func_commit "Cmnd_Alias" $ali "$usr_list"
}
# =============================
# the main user friendly interface
# =============================
echo "========================================================================"
echo "The utility will ask you to input entries; please enter them accordingly"
echo "WARNING!! Please make sure that you do know about $sudoers file and"
echo "you know what you are doing; sudo will not work if entries in $sudoers"
echo "are incorrect and that might lead to a security hole in your system"
echo "========================================================================"
# the big while loop
while : ; do
echo
echo "Please enter an appropriate number corresponding to the operation"
echo "1 Add a User to sudoers"
echo "2 Add a Group to sudoers"
echo "3 Create a User Alias"
echo "4 Create a Runas Alias"
echo "5 Create a Host Alias"
echo "6 Create a Command Alias"
echo "7 Exit out of this wizard"
echo ; echo -n "Enter: "
read hit
case $hit in
1 )
func_user
func_mrc
func_write $usr_name $sys_name $rusr_name $cmd_name;;
2 )
func_group
func_mrc
func_write $grp_name $sys_name $rusr_name $cmd_name;;
3 )
func_create_user_alias;;
4 )
func_create_runas_alias;;
5 )
func_create_host_alias;;
6 )
func_create_cmnd_alias;;
7 ) break;;
* ) echo "Error: wrong number";;
esac
done
## dont forget to remove the lock file we created long back ;-)
rm -f $sudoers.tmp
exit 0
