[cs631apue] HW5 questions
rhoffman at stevens.edu
Thu Dec 8 15:22:09 EST 2011
Last question, I promise.
In your hw specs you mention "if the patch was already applied, running
'make' won't do this again etc". After reading through the man pages &
Google for diff/patch again and again I don't see any way to tell
whether or not a file has been patched already before running the patch
command, because there is no original file to do a diff or cmp against.
Now, if we're allowed to keep backups of the old files upon the initial
patching (I can't tell from the hw description) then I'll just do that
and call it a day.
If not, then it is my understanding that patch can tell if a file is
already patched with the -N flag. But, if it finds that any/all files
are already patched it returns a positive error code. This in turn
causes make to error and abort. I know that the error can be ignored by
preceding the patch command with a '-', but I'm not sure if this type of
approach is good practice.
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