Notes

#!/bin/bash
#!/bin/bash
clear #clearing the screen
green=$( tput setaf 2 ) #Assigning tput green color attribute to green variable
red=$( tput setaf 1 ) #Assigning tput red color attribute to red variable
mag=$( tput setaf 5 ) #Assigning tput magenta color attirbute to mag variable
bold=$( tput bold) #Assigning bold attribute tp bold variable
rev=$( tput rev ) #Assigning reverse mode attribute to rev variable
defColor=$( tput sgr0 ) #Assigning tput default color attribute to the defColor variable

function user_password
{
if [ "$1" != '' ];
then
username=$1;

else
read -p "Enter the username to change password: " username
fi
passwd "$username"
}

function add_user
{
read -p "Enter Username: " username
useradd "$username"
user_password "$username"
uid=`id -u "$username"`
echo "${green}User Added Successfully with user ID :${rev}${bold}${uid}${defColor}"
}

function del_user
{
read -p "Enter Username: " username
userdel "$username"
echo "${green}User ${bold}${username}${defColor}${green} has been deleted successfully${defColor}"
}

function username_change
{
read -p "Enter current username to change: " curusr
read -p "Enter new username: " newusr
usermod -l "newusr" "curusr"
echo "${green}Username changed from ${bold}${curusr}${red}-->${green}${newusr}${defColor}"
}

function uid_change
{
read -p "Enter username whose UID you want to change: " curusr
curuid=`id "$curusr" | grep -oP 'gid=KS+'`
read -p "Enter new UID: " newuid
usermod -u "$newuid" "$curusr"
echo "${green}UserID changed from ${bold}${curuid}${red}-->${green}${newuid}${defColor}"
}

function get_gid
{
groupname=$1
#searching for groupname in /etc/group and then extracting the GID using sed
gid=$( sed -nr "s/^$groupname:x:([0-9]+):.*/1/p" /etc/group ) #stream editing with sed
#sed searches for the line where there is the given groupname and extracts the GID
echo "$gid"
}
function grpname_change
{
read -p "Enter current Group name to change: " curgrp
read -p "Enter new Group name: " newgrp
groupmod --new-name "$newgrp" "$curgrp"
echo "${green}Group name changed from ${bold}${curgrp}${red}-->${green}${newgrp}${defColor}"
}

function grpid_change
{
read -p "Enter Group name whose ID you want to change: " curgrp
curgid=`get_gid "$curgrp"`
read -p "Enter new Group ID: " newgid
groupmod -g "$newgid" "$curgrp"
echo "${green}Group ID changed from ${bold}${curgid}${red}-->${green}${newgid}${defColor}"
}

function del_grp
{
read -p "Enter Group name: " grpname
groupdel "$grpname"
echo "${green}Group ${bold}${grpname}${defColor}${green} has been deleted successfully${defColor}"
}

function edit_user
{
clear
echo "1. Change Username "
echo "2. ${rev}Change Password ${defColor}"
echo "3. Change UID"
echo "4. ${rev}Back to main menu${defColor}"
read -p "Enter any option from [1-3]: " opt
if [[ "$opt" =~ ^[1-4]{1}$ ]];
then
case "$opt" in
1) username_change;;
2) user_password;;
3) uid_change;;
4);;

esac
echo
echo
else
echo "${red}Invalid Input${defcolor}"
fi
}

function add_grp
{
read -p "Enter Groupname: " grpname
groupadd "$grpname"
gid=`get_gid "$grpname"`
echo "${green}Group Added Successfully with group ID :${rev}${bold}${gid}${defColor}"
}

function edit_grp
{
clear
echo "1. ${rev}Change Group name${defColor} "
echo "2. Change Group ID$"
echo "3. ${rev}Back to main menu{defColor}"
read -p "Enter any option from [1-3]: " opt
if [[ "$opt" =~ ^[1-3]{1}$ ]];
then
case "$opt" in
1) grpname_change;;
2) grpid_change;;
3);;

esac
echo
echo
else
echo "${red}Invalid Input${defcolor}"
fi
}

function grp_assign
{
read -p "Enter the username which you want to assign to a group: " username
read -p "Enter the group name in which you want to assign the user: " groupname
usermod -a -G "$groupname" "$username"
echo "${green}USER ${bold}${username}${defColor}${green} has been assigned to ${bold}${groupname}${defColor}"
}

function grpuser_remove
{
read -p "Enter the username: " username
read -p "Enter the group from where you want to remove user: " groupname
deluser "$username" "$groupname"
}

function list_user
{
echo "${mag}${bold}The User list is${defColor}"
echo
cut -d: -f1 /etc/passwd | more
}

function list_grp
{
echo "${mag}${bold}The Group list is${defColor}"
echo
cut -d: -f1 /etc/group | more
}
clear
figlet Account Management
flag="Y"
while [ $flag == "Y" ]; do
echo "1. Add User "
echo "2. ${rev}Edit user ${defColor}"
echo "3. Delete User "
echo "4. ${rev}Add Group ${defColor}"
echo "5. Edit Group "
echo "6. ${rev}Delete Group ${defColor}"
echo "7. Assign Users to Group "
echo "8. ${rev}Remove Users From Group ${defColor}"
echo "9. List users "
echo "10.${rev}List groups ${defColor}"
echo "11.Exit "
echo
read -p "Enter any option from [1-11]: " opt
if [[ "$opt" =~ ^[0-9]+$ ]];
then

case "$opt" in
1) add_user;;
2) edit_user;;
3) del_user;;
4) add_grp;;
5) edit_grp;;
6) del_grp;;
7) grp_assign;;
8) grpuser_remove;;
9) list_user;;
10) list_grp;;
11) exit;;
esac
echo
echo
continue
else
echo "${red}Invalid Input${defColor}"
continue
fi
done