How to use cat command to view file contents?

Using the cat Command to View File Contents

The cat command, short for "concatenate", is a powerful tool in the Linux command-line interface (CLI) that allows you to view the contents of a file. It is one of the most commonly used commands in the Linux ecosystem, and understanding how to use it effectively is essential for any Linux user or administrator.

Viewing the Contents of a File

To use the cat command to view the contents of a file, simply type cat followed by the file name. For example, if you have a file named example.txt, you can view its contents by running the following command:

cat example.txt

This will display the entire contents of the example.txt file on your terminal screen.

Viewing Multiple Files

The cat command can also be used to view the contents of multiple files at once. To do this, simply list the file names separated by a space after the cat command. For example:

cat file1.txt file2.txt file3.txt

This will display the contents of file1.txt, file2.txt, and file3.txt one after the other in your terminal.

Viewing Hidden Files

In Linux, files and directories that begin with a dot (e.g., .bashrc) are considered hidden files. To view the contents of a hidden file using the cat command, you can use the following syntax:

cat .hidden_file.txt

Alternatively, you can use the -a (or --all) option to display all files, including hidden ones:

cat -a

This will show the contents of all files in the current directory, including hidden files.

Viewing File Contents with Line Numbers

Sometimes, it can be helpful to have line numbers displayed when viewing the contents of a file. You can achieve this by using the -n (or --number) option with the cat command:

cat -n example.txt

This will display the contents of example.txt with line numbers.

Viewing File Contents in Reverse Order

The cat command can also be used to display the contents of a file in reverse order. To do this, use the -r (or --reverse) option:

cat -r example.txt

This will display the contents of example.txt in reverse order, starting from the last line.

Viewing File Contents with Highlighting

If you want to view the contents of a file with syntax highlighting, you can use a tool like less or more instead of cat. These tools provide more advanced features for viewing and navigating file contents. For example, to view a file with less and syntax highlighting, you can use the following command:

less -N example.txt

This will display the contents of example.txt with line numbers and syntax highlighting (if the file type is recognized).

In summary, the cat command is a versatile tool for viewing the contents of files in the Linux CLI. By understanding its various options and use cases, you can efficiently navigate and inspect files on your system.