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Useful command arguments undocumented in man


Hello all, currently working through the labs for this course, and when going through Lab 6.2 for RPM ("Rebuilding the RPM Database"), I couldn't find anything in the rpm man pages that covered the --rebuilddb switch, or under rpm --help. This is on CentOS 7.

It's possible I just need new glasses, but this made me wonder if there is such a thing as a list of useful commands that are not necessarily well documented on the tools available during the exam, and are worth spending extra time getting to grips with?



  • lee42x
    lee42x Posts: 380

    Hello dacarab,
    Well not actually hidden, but easy enough to find. I believe the lecture notes mentioned a command "rpmdb", this is the one you are looking for. Now to find commands you might not know, start with the ones you do know like "rpm". If you run " man rpm" , it will give you the manual page for that command, now look near the bottom of the page and you will find a "SEE ALSO" section that will list related commands. Yes, "rpmdb" is in the list.

    My personal favorite commands are; find, grep and man. Something like "man -wK rebuilddb" will show which man page contains the phrase "rebuilddb"


  • coop
    coop Posts: 915

    The exact command seems to depend on version of Fedora or RHEL/CentOS. I was not even aware there was an "rpmdb" command :) There has always been an option to rebuild the data base under either "rpm" or "rpmbuild" (The course says to use "rpm --rebuild". On my system (RHEL 8) sudo rpm --rebuilddb clearly works; sudo rpm --rebuild seems to be a no-op. Go figure. sudo rpmdb --rebuild seems to do the trick. Must be the preferred way since the man page for rpm does not mention the rebuild thing. Once again, go figure :)

  • dacarab
    dacarab Posts: 8

    Nice one - I hadn't thought to try man -Kto search through, that's a good tip. Cheers


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