Re: Does diff generate diff or patch files?

[Hans-Bernhard Broeker]

Bob Rossi <address@hidden> wrote:

> This slightly confuses me. I'll
> have to try to determine when it's best to call the output of diff a
> `diff' and when it's called a `patch'.

You worry too much. ;-) But OK, let's be nitpickingly, over-abundantly
clear about it:

* diff generates diffs.  Not "diff files", because it doesn't generate
a file, it just send texts to its standard output.  If, and only if,
the diff is redirected into a file, it turns into a "diff file".

* patch applies patches (from its stdin channel) or patch files (from
named files).  

* Some fiendishly clever guy made the input format(s) of patch
resemble very closely the output format(s) of diff.

So the output of diff is a diff, the input of patch is a patch.  But a
large fraction of all diffs that get generated is never get fed to
patch. So the difference, if one really wants to make any, between a
diff and a patch, has nothing to do with the file itself.  The only
distinction betwen the two is the decision of somebody to take /this/
diff, and use it to patch /that/ file.

Summing it up: there's no difference whatsoever between a diff and a
patch.  If they can be distinguished at all, it's only by their usage.

-- 
Hans-Bernhard Broeker (address@hidden)
Even if all the snow were burnt, ashes would remain.