Lesson 2.2: Use Looping constructs (for, etc.) to process file, command line input

Example 1: Create users and set the password to same as the username, but expire the password in first logon.The user list should be stored in a txt file.

 
[root@client scripts]# cat developers
developer1
developer2
developer3
developer4
developer5
developer6
developer7
developer8
developer9
developer10
 
[root@client scripts]# cat developeradd.sh 
for i in $(cat /home/sanjeeb/scripts/developers)
do
	useradd $i
	echo $i | passwd --stdin $i
	chage -d 0 $i
done
echo "Developers account created" 
 
[root@client scripts]# cat /etc/passwd
developer1:x:1003:1003::/home/developer1:/bin/bash
developer2:x:1004:1004::/home/developer2:/bin/bash
developer3:x:1005:1005::/home/developer3:/bin/bash
developer4:x:1006:1006::/home/developer4:/bin/bash
developer5:x:1007:1007::/home/developer5:/bin/bash
developer6:x:1008:1008::/home/developer6:/bin/bash
developer7:x:1009:1009::/home/developer7:/bin/bash
developer8:x:1010:1010::/home/developer8:/bin/bash
developer9:x:1011:1011::/home/developer9:/bin/bash

Example 2: Deleting the recently added users

 
[root@client scripts]# cat deleteusers.sh 
for i in $( cut -f 1 -d: /home/sanjeeb/scripts/userslist.txt )
do
	userdel $i
	echo "User $i deleted !" 
done
 
[root@client scripts]# deleteusers.sh 
User developer1 deleted !
User developer2 deleted !
User developer3 deleted !
User developer4 deleted !
User developer5 deleted !
User developer6 deleted !
User developer7 deleted !
User developer8 deleted !
User developer9 deleted !
User developer10 deleted !