How to display line numbers in cat command?

Displaying Line Numbers in the cat Command

The cat command in Linux is a versatile tool used to display, concatenate, and create files. By default, the cat command does not display line numbers. However, you can easily add line numbers to the output using the -n or --number option.

Here's how you can display line numbers with the cat command:

cat -n file.txt

This will display the contents of the file.txt file with line numbers. The output will look similar to this:

     1  This is the first line.
     2  This is the second line.
     3  This is the third line.

Alternatively, you can use the --number option, which produces the same result:

cat --number file.txt

The --number-nonblank option can also be used to display line numbers, but it will only show line numbers for non-empty lines:

cat --number-nonblank file.txt

This will result in the following output:

     1  This is the first line.
     2  This is the second line.
     3  This is the third line.

Here's a Mermaid diagram that illustrates the different options for displaying line numbers with the cat command:

Using the cat command with line numbers can be particularly helpful when working with code files, log files, or any other text-based content where line numbers can provide valuable context and make it easier to reference specific lines.

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