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kolypto
Asked: 2009-11-09 21:52:33 +0800 CST

Linux: how to restore config file using apt-get/aptitude?

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I've occasionally lost my config file "/etc/mysql/my.cnf", and want to restore it. The file belongs to package mysql-common which is needed for some vital functionality so I can't just purge && install it: the dependencies would be also uninstalled (or if I can ignore them temporarily, they won't be working).

Is there a way to restore the config file from a package without un-ar-ing the package file?

dpkg-reconfigure mysql-common did not restore it.

linux

7 Answers

  1. Best Answer

    dpkg -i --force-confmiss mysql-common.deb will recreate any missing configuration files, ie /etc/mysql/my.cnf in your case.

    • 39

  2. None of the above worked for me - maybe outdated - anyway, I found this solution:

    apt-get -o Dpkg::Options::="--force-confmiss" install --reinstall mysql-common
    • 18

  3. In Debian Squeeze — at least —, we also can do it this way, after su — or sudo for Ubuntu —

    aptitude install -o Dpkg::Options::=--force-confmiss mysql-server

    This will care for the dependencies of mysql-server and reset all the missing conf files of the lot, including mysql-common. Conflicting (remaining) files will be prompted out to be kept or reset.

    Unfortunately, there is a bug in aptitude, and 

    aptitude purge -o Dpkg::Options::=--force-all mysql-server

    will not work. So we have to do it one by one with 

    dpkg --force-all --purge  mysql-common  mysql-server  mysql-client …

    This will remove any config file, original or modified, but custom files will be preserved, with an onscreen message. Note, by the way, that dpkg also recognizes --force-confnew and --force-confold options.

    To get mysql-server dependencies' list print on screen :

    aptitude --simulate remove mysql-server
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  4. You can find default mysql config files in /usr/share/doc/mysql-server-5.0/examples/ or similar. That may be all that you need unless you have some really special/esoteric configurations enabled.

    • 3

  5. In my /etc/mysql/ directory, I have a my.cnf.orig file which contains the original contents of my.cnf.

    I'm not sure where /etc/mysql/my.cnf.orig came from - that is, whether I created it, or the installation of mysql did it. I remember checking at one time that it was exactly the same as my.cnf

    If you have such a thing, and no my.cnf you can copy one to the other.

    sudo cp /etc/mysql/my.cnf.orig /etc/mysql/my.cnf

    In any case, it's a simple text file of 3897 bytes and you could copy and paste from a generic Mysql configuration file.

    It will be a good idea once you restore your /etc/mysql/my.cnf to make a copy so you can restore it easily in future.

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  6. You need to reinstall mysql-common with this command:apt-get install --reinstall mysql-common

    • 0

  7. It appears some of the other solutions won't work if the configuration files of the package are managed with ucf.

    In this case you can use :

    UCF_FORCE_CONFFMISS=1 apt-get --reinstall install [pkgname]
    • 0