Getting back my system from a kernel crash

Upgrading a package from the pacman cache after a system crash on a new package install.

Today I happened to face a system crash on my arch linux setup. I wanted to use dig, but the program complained of a missing dependency:

➜ dig
 dig: error while loading shared libraries: libjson-c.so.3: cannot open shared object file: No such file or directory

Then, I decided to upgrade the json-c library.

➜ _ pacman -S json-c

It was installed (overriding the existing version 2), and I was happy it worked. Until I shutdown my machine:

Feb 15 14:37:10 archlinux systemd[1]: Starting Power-Off...
Feb 15 14:37:10 archlinux systemctl[1207]: /usr/bin/systemctl: error while loading shared libraries: libjson-c.so.2: cannot open shared object file: No such file or directory
Feb 15 14:37:10 archlinux systemd[1]: systemd-poweroff.service: Main process exited, code=exited, status=127/n/a
Feb 15 14:37:10 archlinux systemd[1]: systemd-poweroff.service: Failed with result 'exit-code'.
Feb 15 14:37:10 archlinux systemd[1]: Failed to start Power-Off.

:scream:

I was doubtful that I had screwed up my machine. So, I quickly restarted the machine, to my happiness, it was indeed !!. :innocent: :gun:.

Fixing

Fixing this was easy and speasy, just boot in with a liveboot USB and do:

pacman -U #<path to the old jsonlibtar file in the cache>

Why this post?

This is just a rubber ducking post. Over the course, I learnt to find how to find all the packages that are dependant on a given one:

pactree -r <package>

Dependant packages

pacman -Qil #Package Name

Lists all the files and other meta information for an installed package on the system

Changes