The cat command in Ubuntu Linux with examples

This article explains using the cat command in Ubuntu Linux to view file content. It also provides some examples for you to try.

The cat command in Linux is a command line utility that allows you to view the contents of a file, create new files, concatenate files, and even append text to existing files. Its name is derived from “concatenate,” which reflects its main functionality of combining multiple files.

The primary use of the cat command is to display the contents of one or more files in the terminal. It’s a simple and efficient way to quickly view the contents of a file without having to open it in an editor.

Additionally, the command provides a versatile set of features to manipulate and view file contents, making it a valuable tool for developers, system administrators, and users.

Syntax

The basic syntax of the cat the command is as follows:

cat [OPTION]... [FILE]...

The command OPTION specifies various options that can modify the behavior of the command and FILE refers to the file or files on which you want to perform operations.

Viewing file contents

The primary use of the cat command is to display the contents of one or more files in the terminal. To view the contents of a file, specify the file name as an argument:

cat file.txt

Creating a new file

Using cat, you can create a new file and enter text into it directly from the command line. To do so, type cat followed by the redirection operator (>), and the name of the file you wish to create.

Press Enter, and then start typing your text. Finally, press Ctrl + D save and exit the file.

cat > newfile.txt
This is some example text.

Press Ctrl + D to save and exit when you’re done typing.

Concatenating files

The cat command can also be used to concatenate multiple files into one. To do this, list the names of the files you want to combine as arguments, separating them with spaces:

cat file1.txt file2.txt > combined.txt

This command will concatenate the contents of file1.txt and file2.txt into a new file named combined.txt.

Appending text to a file

If you want to add text to the end of an existing file without overwriting its contents, you can use the append operator (>>). This is especially useful when adding content to a log or configuration file.

cat >> file.txt
This text will be appended to the end of the file.

Press Ctrl + D to save and exit.

Line numbers

By using the -n option, you can display the lines of a file preceded by line numbers. This is particularly helpful when analyzing log files or large code files.

cat -n file.txt

That should do it!

Conclusion

• The cat command in Ubuntu Linux is a versatile and powerful tool for viewing, creating, manipulating, and combining file contents.
• Its simple syntax and variety of options make it efficient for developers, system administrators, and users.
• With cat, you can quickly view file content, create new files, concatenate files, append text to existing files, and display lines preceded by line numbers.
• Understanding and mastering the cat command can significantly enhance your efficiency when working with files and the command line in Ubuntu Linux.