4

I reinstall emacs by compiling its source and then sudo checkinstall. I found checkinstall creates a file

-rw-r--r--  1 root root 44628516 Apr 22 19:19 emacs_24.5-1_amd64.deb
-rw-r--r--  1 root root 56991208 Apr 22 19:19 backup-042220151919-pre-emacs.tgz

Does checkinstall create a backup file regardless of which software it installs, or it depends on specific software (e.g. emacs) (maybe depending on the specific Makefile?)?

What is the backup file for?

Shall I keep it, and when can I discard it?

How shall I use it in case it is needed?

4

When you install package with checkinstall, it will automatically make a backup tarball of the currently installed package, if exists (it depends on ./configure --prefix=/dir). The name is: backup-<datetime>-pre-<packagename>-<version>.tgz in directory you are building package. If anything goes wrong with your new package you can roll back to the previous version using:

tar -xzvf backup-<datetime>-pre-<packagename>-<version>.tgz -C /

It is up to you how long you will keep this backup.

Additional info:

  1. When you run checkinstall it asks you a couple of question and there is:

    This package will be built according to these values:

     ...
     3 -  Version: [ x.y.z ]
     ...
    

So your backup should be: backup<datetime>-pre-<packagename>-x.y.z. Note the word pre.

  1. If the installed package is installed in /usr/bin and your --prefix=/usr/local/ checkinstall will not backup package installed in /usr/bin.

  2. I think your backup archive is relative to /. And

    tar -xzvf backup-<datetime>-pre-<packagename>-<version>.tgz -C /

will need sudo because it will place files in folders to which ordinary users don't have write permission.

  • Thanks! (1) Why does my backup file not have <version> in its name? (2) does checkinstall back up the installed one, only when the installed one exist in the --prefix=/dir where the new one will be installed? If the installed one exist in other directory, will checkinstall still back it up? (3) when roll back, does tar -xzvf backup-<datetime>-pre-<packagename>-<version>.tgz -C / need sudo? Why change to / by -C /? Isn't my previous --prefix, which is generally either /usr or /usr/local. – Tim Apr 23 '15 at 13:12
  • @Tim answer is edited. – taliezin Apr 23 '15 at 13:41
  • does tar -xzvf backup-<datetime>-pre-<packagename>-<version>.tgz -C / need sudo – Tim Apr 23 '15 at 13:58
  • It is in the third point. – taliezin Apr 23 '15 at 13:59
  • the third one is whether checkinstall needs sudo. not tar -xzvf backup-<datetime>-pre-<packagename>-<version>.tgz -C / need sudo – Tim Apr 23 '15 at 14:24

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