HowTo: Linux Random Password Generator Command

Tutorial details
Difficulty	Easy (rss)
Root privileges	No
Requirements	Bash
Time	2m

1. /dev/urandom file – Linux kernel’s random number generator source/interface. A read from the /dev/urandom device will not block waiting for more entropy.
2. tr command – Translate or delete characters. Used to remove unwanted characters from /dev/urandom.
3. head command – Output the first part of files.
4. xargs command – build and execute command lines from standard input/pipe.

Bash function to create random password

Edit ~/.bashrc file, enter:
$ vi $HOME/.bashrc
Append the following code:

genpasswd() { 
	local l=$1
       	[ "$l" == "" ] && l=16
      	tr -dc A-Za-z0-9_ < /dev/urandom | head -c ${l} | xargs 
}

Save and close the file. Source ~/.bashrc again, enter:
$ source ~/.bashrc

To generate random password, enter:
$ genpasswd
Sample outputs:

WGtkhETPJFZ2mtZk

To generate 8 character long random password, enter:
$ genpasswd 8
Sample outputs:

oj7Wqvb

Linux Random Password Generator Command

• See how to use makepasswd> command to generate true random passwords by using the /dev/random feature of Linux.
• Man pages: urandom(4)