ow do I change my own password as well as the passwords of other 
users as required under Linux operating system without using GUI 
systems?
 
 You can use the passwd 
command to change your password, and, as a system administrator, change 
the password of the root account, or another user in your Linux system. 
The syntax is as follows:
passwd passwd {userName}
Task: Linux Change Your Own Password
Login using the 
ssh client or open a command-line terminal (select Applications > 
Accessories > Terminal), than type the following command:
 $ passwd
 First, the user is prompted for their current password.  If the current
 password is correctly typed, a new password is requested.  The new 
password must be entered twice to avoid typing errors. Running passwd 
command with no arguments will allow you to change your own password.
Task: Linux Change root's User Password
To
 change root's password, you must first login as root user or use sudo /
 su command to obtain root's credentials. To become the root user, 
enter:
 $ su -l
 OR
 $ sudo -s
 Next, to change root's password, enter:
 # passwd
 WARNING! You can change root's password only if you are logged in as the root user!
WARNING! You can change root's password only if you are logged in as the root user!Task: Linux Change Another User's Password
To change the password of another user, login as root and type:
 # passwd userNameHere
 # passwd tom
 # passwd jerry
Getting Help
Anytime
 you need assistance with Linux passwd command-line, turn to the man 
page first. It will give you detailed information, parameters and 
switches for passwd command. For example, man passwd opens the man page 
for the passwd command:
 $ man passwd
 $ man 5 passwd
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