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

History

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. It first appeared in 1BSD of 1977.
The version of fold bundled in GNU coreutils was written by David MacKenzie.

Example

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

fold -w 50 file.txt


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