The Linux command paste is one of the powerful commands that can be used to “merge multiple files in to a single file” and also “collapse multiple lines in a single file to a new file”. Here are some basic examples of using the paste command.
Paste command to merge multiple files into a single file
Let us say you have two files.
>cat last_names.txt Smith Jones
>cat first_names.txt John David
We can use paste command to merge each line in these two files into a single file
>paste last_names.txt first_names.txt Smith John Jones David
By default, paste commands merges two file with tab delimiter. We can also specify a delimiter with using “-d” option. For example, to use comma as delimiter
>paste -d"," last_names.txt first_names.txt Smith,John Jones,David
Paste command to join N lines of a file
paste command can also be used with single file (instead of multiple) to join multiple lines from a file. Let us say we have a file like this
>cat numbers.txt One Two Three Four Five Six
We can use paste command to merge multiple lines, say every three lines, into a single line
>less numbers.txt | paste - - - One Two Three Four Five Six
The less command on the file feeds the content of the file numbers.txt to the paste
command. The three dashes “- – -” in the above paste command merges three lines. If we want
to merge every two lines, we will use two dashes like this
>less numbers.txt | paste - - One Two Three Four Five Six
