How To Join Files In Linux

In many situations, you might need to combine the contents of multiple files into a single file. Fortunately, Linux provides a set of powerful utilities that can help you to achieve this task effortlessly. In this blog post, we are going to discuss how to join files in Linux.

The ‘cat’ Command

The simplest way to join files in Linux is to use the cat (short for concatenate) command. This command not only allows you to display the content of a file but also can be used to merge the contents of multiple files.

$ cat file1.txt file2.txt > joinedfile.txt

In the above example, the contents of file1.txt and file2.txt are combined and the output is redirected to a new file named joinedfile.txt. If the output file already exists, it will be overwritten.

The ‘join’ Command

While the cat command is useful, it simply concatenates files line by line. If you want to join two files based on a common field, you should use the join command.

$ join file1.txt file2.txt

The join command in the above example merges lines from both files which have common fields. By default, the join command treats whitespace as a field delimiter and it assumes that the input files are sorted based on the join fields.

The ‘paste’ Command

The paste command is another useful utility for merging files in Linux. Unlike the cat command, which concatenates files line by line vertically, the paste command merges files horizontally line by line.

$ paste file1.txt file2.txt

In the example above, paste combines each line from file1.txt with the corresponding line from file2.txt. By default, it uses a tab character to separate concatenated lines.


In this blog post, you have learned how to join files in Linux using the cat, join, and paste commands. While these commands are quite simple, they are very powerful and can be used to efficiently manipulate files in Linux. Remember to always back up your data before performing any file operations to prevent data loss.