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This article covers how to use the Linux cat command. Cat(concatenate) command is very frequently used in Linux. It reads data from the file and gives their content as output. It helps us to create, view, concatenate files.

If you want to add a bit of new text to an existing text file, you use the cat command to do it directly from the command line (instead of opening it in a text editor).

Type the cat command followed by the double output redirection symbol ( >> ) and the name of the file you want to add text to.



This article covers how to use head command with all required options. 

By using the tail command with a head command, you can also display the last lines of a file on the terminal.

The head command, as the name implies, print the top N number of data of the given input. 

By default, it prints the first 10 lines of the specified files. 

If more than one file name is provided then data from each file is preceded by its file name. 


Head command Syntax:

head [OPTION]... [FILE]...



This article covers how Wall command works in Linux. Wall is a handy utility that helps a multi-user system admin to quickly notify other users to save their work before a system shutdown or reboots. 

Here, you will see some examples of how to use the wall command to communicate with logged-in users.

There are times when multiple users are logged in to a server computer, and you - the system/network admin - need to, say, restart the server to perform some maintenance task. 

Of course, the correct way is to inform all those who are logged in about the maintenance activity.

In Linux, there is a built in command line utility for this purpose called Wall.


What is wall command in Linux ?

As already mentioned, the wall command is used to send a message to all logged in users. 

It's syntax is:

$ wall [-n] [-t TIMEOUT] [file]


How to use wall command?

Basic usage is very straight forward - just execute the 'wall' command and write the message you want to transmit on the standard input. 

Once done, use the Ctrl+D key combination to signal the command that you're done writing the message: 

$ wall


How to remove header from broadcasted message?

In case you want to remove the header that appears with the broadcasted messages, you can do that using the -n command line option:

$ wall -n



This article will guide you on how to use the #wc #command in #Linux. Here you will learn the basics of wc command along with its command-line options and few practical examples. Now you can easily count number of lines, words, characters and bytes in your files and in the output from other commands. The wc command in #UNIX is a command line utility for printing newline, word and byte counts for files. It can return the number of lines in a file, the number of characters in a file and the number of words in a file. It can also be combine with pipes for general #counting operations. To use use WC command, you need to know the following: wc -l : Prints the number of lines in a file. wc -w : prints the number of words in a file. wc -c : Displays the count of bytes in a file. 1. A Basic Example of WC Command. 2. Count Number of Lines. 3. Display Number of Words. 4. Count Number of Bytes and Characters. 5. Display Length of Longest Line.




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