diffutils: More or Fewer Messages
10.11.1 Controlling the Verbosity of 'patch'
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You can cause 'patch' to produce more messages by using the '--verbose'
option. For example, when you give this option, the message 'Hmm...'
indicates that 'patch' is reading text in the patch file, attempting to
determine whether there is a patch in that text, and if so, what kind of
patch it is.
You can inhibit all terminal output from 'patch', unless an error
occurs, by using the '-s', '--quiet', or '--silent' option.