/etc/shadow HowTo - Linux / Unix Q & A from nixCraft

userdel: user vivek is currently used by process 749 error and fix on Linux

last updated September 22, 2017 in CentOS, Debian / Ubuntu, Linux, Suse, User Management

I am trying to delete a user named vivek using the userdel command as follows

userdel -r vivek
userdel: user vivek is currently used by process 749

How do I fix this problem and delete username vivek on a Debian Linux 9.x server?

How to change root password in Ubuntu Linux

last updated January 9, 2018 in Linux, Ubuntu Linux

I am a new Ubuntu Linux server admin. How can I change root password in Ubuntu Linux server using the bash shell over ssh based session?

How to force users to use secure passwords on Ubuntu/Debian Linux

last updated August 29, 2016 in Debian / Ubuntu, Linux, Security, User Management

My Linux shell user can modify their password using the passwd command. How can I force users to choose the secure password that will prevent users from using stupid passwords like “abc123”, “password”, “123456” and so on? How do I setup password quality requirements on my Debian or Ubuntu Linux server?

Linux Change Password

last updated July 29, 2013 in BASH Shell, Commands, Linux

How do I change my own password as well as the passwords of other users as required under Linux operating system without using GUI systems? How can I change or set user password on Linux operating systems?

Ubuntu: Rename an Account [ User ID ]

last updated December 6, 2010 in Ubuntu Linux

How do I rename a user name from ‘tom’ to ‘jerry’ under Ubuntu Linux?

Linux Upgrade Password Hashing Algorithm to SHA-512

last updated November 12, 2009 in CentOS, Linux, RedHat and Friends, Security, User Management

The default algorithm for storing password hashes in /etc/shadow is MD5. I was told to use SHA-512 hashing algorithm. How do I set password hashing using the SHA-256 and SHA-512 under CentOS or Redhat Enterprise Linux 5.4?

How To: UNIX Add A User To A Group

last updated June 16, 2008 in AIX, FreeBSD, HP-UX Unix, Solaris-Unix, UNIX

How do I add a user to a group under Sun Solaris UNIX operating system from a shell prompt or command line?