Originally shared by César Bustíos BenitesFunny and interesting Linux command line utilities
Working on Linux command line can be fun sometimes. Ubuntu Linux is used for all the examples. Enjoy at your own risk!:
1. Linux "sl" command
From the man page: "sl - display animations aimed to correct users who accidentally enter sl instead of ls."
$ sudo apt-get install sl
$ sl
(see image)
Animated steam locomotive loving across the screen from right to left. One can play a prank on someone by:
$ alias ls=sl
2. Linux "yes" command
From the man page: "yes - output a string repeatedly until killed"
$ yes linux
linux
linux
linux
linux
^C
$
Why would we want a command to keep on printing a string all the life of the process? We can use "yes" command in certain scripts where we want to feed the same answer in a repeated operation. For example, we are doing an operating on a set of files and Linux asks us to confirm for each and every file. We can auto-feed a yes using the "yes" command.
3. Linux "rev" command
From the man page: "rev — reverse lines of a file or files"
It reverses all the input strings given to it line by line. To play around, type the command "rev" on the command prompt and press enter:
$ rev
Linux
xuniL
google+
+elgoog
^C
$
This command also takes the input in the form of a file, where it reverses all the strings line wise in the file and prints the output to the standard output:
$ cat strings.txt
Linux is so much fun!
Happy Birthday
$ rev strings.txt
!nuf hcum os si xuniL
yadhtriB yppaH
4. Linux "fortune" command
From the man page: "fortune - print a random, hopefully interesting, adage"
The fortune command is in the same lines as fortune cookies. We get a random adage or a message when we run this command:
$ sudo apt-get install fortune
$ fortune
You have the power to influence all with whom you come in contact.
$ fortune
You'd like to do it instantaneously, but that's too slow.
5. Linux "figlet" command
From the man page: " FIGlet - display large characters made up of ordinary screen characters"
This displays our input string in large characters as banners formed out of ASCII characters:
$ sudo apt-get install figlet
$ figlet Google+
(see image)
One can add such banners in the scripts headers or sources using "figlet".
6. Linux "toilet" command
From the man page: "TOIlet - display large colourful characters"
It's a very colourful command. Similar to "figlet", it displays our text as banners but in a prettier way:
$ sudo apt-get install toilet
$ toilet Google+
(see image)
It has some colours to offer too. Let's see by running following command:
$ toilet -f mono12 -F metal Google+
(see image)
7. Linux "cowsay" command
From the man page: "cowsay/cowthink - configurable speaking/thinking cow (and a bit more)"
The "cowsay" command is an amusing command. It depicts the power of ASCII characters to draw a cow, sheep, and many other animals. However it might not always be present in every distribution of Linux:
$ sudo apt-get install cowsay
$ cowsay "Google+ is fun"
(see image)
Although the command name suggests a cow, it also offers to draw a sheep:
$ cowsay -f sheep "I too love Google+"
(see image)
To have all the capabilities as to what all animals it can draw, just use:
$ cowsay -l
Cow files in /usr/share/cowsay/cows:
apt beavis.zen bong bud-frogs bunny calvin cheese cock cower daemon default
dragon dragon-and-cow duck elephant elephant-in-snake eyes flaming-sheep
ghostbusters gnu head-in hellokitty kiss kitty koala kosh luke-koala
mech-and-cow meow milk moofasa moose mutilated pony pony-smaller ren sheep
skeleton snowman sodomized-sheep stegosaurus stimpy suse three-eyes turkey
turtle tux unipony unipony-smaller vader vader-koala www
Therefore, we can input any of the above animals with the "-f" option. To make it even more fun, one can pipe fortune message to cowsay:
$ fortune | cowsay
8. Linux "oneko" command
From the man page: "oneko - Creates a cute cat chasing around your mouse cursor."
With this command, we see a cat (Tom?) which is chasing our mouse (the mouse pointer, Jerry?):
$ sudo apt-get install oneko
$ oneko
(see image)
h/t +Rupali Sharma
Working on Linux command line can be fun sometimes. Ubuntu Linux is used for all the examples. Enjoy at your own risk!:
1. Linux "sl" command
From the man page: "sl - display animations aimed to correct users who accidentally enter sl instead of ls."
$ sudo apt-get install sl
$ sl
(see image)
Animated steam locomotive loving across the screen from right to left. One can play a prank on someone by:
$ alias ls=sl
2. Linux "yes" command
From the man page: "yes - output a string repeatedly until killed"
$ yes linux
linux
linux
linux
linux
^C
$
Why would we want a command to keep on printing a string all the life of the process? We can use "yes" command in certain scripts where we want to feed the same answer in a repeated operation. For example, we are doing an operating on a set of files and Linux asks us to confirm for each and every file. We can auto-feed a yes using the "yes" command.
3. Linux "rev" command
From the man page: "rev — reverse lines of a file or files"
It reverses all the input strings given to it line by line. To play around, type the command "rev" on the command prompt and press enter:
$ rev
Linux
xuniL
google+
+elgoog
^C
$
This command also takes the input in the form of a file, where it reverses all the strings line wise in the file and prints the output to the standard output:
$ cat strings.txt
Linux is so much fun!
Happy Birthday
$ rev strings.txt
!nuf hcum os si xuniL
yadhtriB yppaH
4. Linux "fortune" command
From the man page: "fortune - print a random, hopefully interesting, adage"
The fortune command is in the same lines as fortune cookies. We get a random adage or a message when we run this command:
$ sudo apt-get install fortune
$ fortune
You have the power to influence all with whom you come in contact.
$ fortune
You'd like to do it instantaneously, but that's too slow.
5. Linux "figlet" command
From the man page: " FIGlet - display large characters made up of ordinary screen characters"
This displays our input string in large characters as banners formed out of ASCII characters:
$ sudo apt-get install figlet
$ figlet Google+
(see image)
One can add such banners in the scripts headers or sources using "figlet".
6. Linux "toilet" command
From the man page: "TOIlet - display large colourful characters"
It's a very colourful command. Similar to "figlet", it displays our text as banners but in a prettier way:
$ sudo apt-get install toilet
$ toilet Google+
(see image)
It has some colours to offer too. Let's see by running following command:
$ toilet -f mono12 -F metal Google+
(see image)
7. Linux "cowsay" command
From the man page: "cowsay/cowthink - configurable speaking/thinking cow (and a bit more)"
The "cowsay" command is an amusing command. It depicts the power of ASCII characters to draw a cow, sheep, and many other animals. However it might not always be present in every distribution of Linux:
$ sudo apt-get install cowsay
$ cowsay "Google+ is fun"
(see image)
Although the command name suggests a cow, it also offers to draw a sheep:
$ cowsay -f sheep "I too love Google+"
(see image)
To have all the capabilities as to what all animals it can draw, just use:
$ cowsay -l
Cow files in /usr/share/cowsay/cows:
apt beavis.zen bong bud-frogs bunny calvin cheese cock cower daemon default
dragon dragon-and-cow duck elephant elephant-in-snake eyes flaming-sheep
ghostbusters gnu head-in hellokitty kiss kitty koala kosh luke-koala
mech-and-cow meow milk moofasa moose mutilated pony pony-smaller ren sheep
skeleton snowman sodomized-sheep stegosaurus stimpy suse three-eyes turkey
turtle tux unipony unipony-smaller vader vader-koala www
Therefore, we can input any of the above animals with the "-f" option. To make it even more fun, one can pipe fortune message to cowsay:
$ fortune | cowsay
8. Linux "oneko" command
From the man page: "oneko - Creates a cute cat chasing around your mouse cursor."
With this command, we see a cat (Tom?) which is chasing our mouse (the mouse pointer, Jerry?):
$ sudo apt-get install oneko
$ oneko
(see image)
h/t +Rupali Sharma