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Creating and Removing,
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Creating and Removing Files
Sometimes when comparing two directories, a file may exist in one
directory but not the other. If you give diff
the
-N
or --new-file
option, or if you supply an old or
new file that is named /dev/null
or is empty and is dated the
Epoch (1970-01-01 00:00:00 UTC), diff
outputs a patch that
adds or deletes the contents of this file. When given such a patch,
patch
normally creates a new file or removes the old file.
However, when conforming to POSIX (see patch and POSIX),
patch
does not remove the old file, but leaves it empty.
The -E
or --remove-empty-files
option causes
patch
to remove output files that are empty after applying a
patch, even if the patch does not appear to be one that removed the
file.
If the patch appears to create a file that already exists,
patch
asks for confirmation before applying the patch.