expand and unexpand

This lesson needs a file with a real TAB character in it. The easiest way to make one is with printf, where \t means a tab:

$ printf 'name\tcount\ngene1\t42\n' > tabs.txt

Look at it with cat tabs.txt and the columns line up. TABs would usually show a noticeable difference but some text files don't show that well enough, and having TABs in a text file may not be the desired spacing you want. To change your TABs to spaces, use the expand command.

$ expand tabs.txt

The command above will print output with each TAB converted into a group of spaces. To save this output in a file, use output redirection like below.

$ expand tabs.txt > result.txt

Opposite to expand, we can convert back each group of spaces to a TAB with the unexpand command:

$ unexpand -a result.txt