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Linux - Modifying Users
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  Setting your own password 
passwd
  Setting another user's password

Run the following as root:

passwd username
  Adding a user

Run the following as root:

useradd username
  Removing a user

Run the following as root:

userdel username
  Removing a user and its home folder

Run the following as root:

userdel -r username
  Listing groups the current user is in 
groups

More detailed information about user and group numerical IDs can be found with the id command.
  Listing groups a user is in 
groups username

More detailed information about user and group numerical IDs can be found with id username.

Parameters

Parameter Details
username The name of the user. Do not use capital letters, do not use dots, do not end it in dash, it must not include colons, no special characters. Cannot start with a number.

Remarks

  • You cannot remove a logged in user
  • To modify any user but your own, you need root privileges
 

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