How to use cat Command? Fast and Easy Guide

Concatenate is the name of the command used in Linux to show the contents of a file or files in the terminal. The use of cat command can also merge files together and make new ones.

What You Will Find

Basis Syntax:

cat [filename]

Filename can be a name of the file or the full path to a file in a different location. The content of the file is shown on the terminal.

use of cat command — **Note:** Simple example **“cat sample.txt”** shows the content inside the file **“sample.txt”**.

Common Options used with cat command

-n: All output lines are numbered with the -n option and the numbers are assigned to each new line.

use of cat command with -n flag — **Details:** As shown in the example **“cat -n sample.txt”** shows the content of the file **“sample.txt”** with a number for each line.

-s: Repeated empty output lines are suppressed using this option.

use of cat command with -s flag — **Note:** As seen in the example **“file.txt”** has multiple blank lines. With normal **“cat file.txt”** command the content is shown as it is. But using **“cat -s file.txt”** removes the multiple empty lines.

-E: The “$” sign, which serves as a line break indicator, is displayed at the end of each line.

use of cat command with -E flag — The only function of **“-E”** option in **“cat -E file.txt”** is to display **“$”** at the end of each new line. As seen in the example empty line are also counted as new line.

-b: Only non-blank output lines will be numbered using the -b option.

use of cat command with -b flag — **Note:** Using **“cat -b file.txt”** will display number for each new line but skip the empty lines.

-T: Tab characters are displayed as “^I” when the -T option is used.

cat command with -T flag — **Note:** The command **“cat -T newfile.txt”** will display the content of the file and also replace all the **“tabs”** to **“^I”**.

Uses of cat command

to quickly inspect the contents of a file on the terminal.

to display a “$” sign at the end of each line, indicating the end of the line use “-E “option.

The -n option is very helpful when you need to number all output lines.

to number non-blank output lines, the -b option is helpful.

to display tab characters as “^I,” the -T option is helpful.

It’s worth pointing out that the cat command can create new files by rerouting the program’s output to a new file and also concatenate files by giving multiple file names separated by spaces.

concatenate the output of both files. — **“cat file1.txt file2.txt”** will display the contents of both the files.

overwriting a file content — In this example **“cat file2.txt >> file.txt”** will append the content of **“file2.txt”** to **“file1.txt”**. Whereas **“cat file2.txt > file.txt”** will overwrite the content of **“file1.txt”** with the content of **“file2.txt”**.

If you want to know about all the common and important command for the Linux terminal then have a look at the article linked below.

Important Command For Linux

Basis Syntax:

Common Options used with cat command

Uses of cat command

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