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## Invoking `patch`

Normally `patch` is invoked like this:

    patch <patchfile

The full format for invoking `patch` is:

    patch options... [origfile [patchfile]]

You can also specify where to read the patch from with the `-i patchfile` or `--input=patchfile` option. If you do not specify patchfile, or if patchfile is `-`, `patch` reads the patch (that is, the `diff` output) from the standard input.

If you do not specify an input file on the command line, `patch` tries to intuit from the leading text (any text in the patch that comes before the `diff` output) which file to edit. See Multiple Patches.

By default, `patch` replaces the original input file with the patched version, possibly after renaming the original file into a backup file (see Backup Names, for a description of how `patch` names backup files). You can also specify where to put the output with the `-o file` or `--output=file` option; however, do not use this option if file is one of the input files.

- patch Options: Summary table of options to `patch`.