Fold (Unix)

fold is a Unix command used for making a file with long lines more readable on a limited width computer terminal by performing a line wrap.

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  argument is set, the fold command allows the user to set the maximum length of a line.

History
The utility first appeared in 1BSD of 1977 and was originally written by Bill Joy.

fold is part of the X/Open Portability Guide since issue 4 of 1992. It was inherited into the first version of POSIX.1 and the Single Unix Specification.

The version of  bundled in GNU coreutils was written by David MacKenzie.

The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities.

Example
As a usage example, to fold a file named  to have a maximum of 50 characters per line, one could run the following command: