Fold is a Unix command used for making a file with long lines more readable on a limited width terminal. Most Unix terminals have a default screen width of 80, and therefore reading files with long lines could get annoying. The fold command puts a line feed every X characters if it does not reach a new line before that point. If the -w argument is set, the fold command allows the user to set the maximum length of a line.
As a usage example, to fold a file named file.txt to have a maximum of 30 characters per line, one could run the following command: