How to regenerate .desktop files for all applications that are currently installed on system

Question

I accidentally deleted all .desktop files from /usr/share/applications directory.

Is there any way to restore/recover/regenerate it back for all the applications that I have currently installed in my Ubuntu 16.04 LTS laptop?

Answer 1

Since only files extracted from packages are supposed be stored in /usr (but not /usr/local) you can use the package manager to recover all those files:

• dpkg-query -S [PATH] lists all currently installed packages that (used to) have files in [PATH].

• With a bit of mangling we can pass the package names to apt-get to reinstall them:

  xargs -r -d '\n' -a <(
      dpkg-query -S /usr/share/applications/ <&- |
      gawk -F '[,:][ \t]' '{ for (i=1; i<NF; i++) if (!a[$i]++) print $i; }'
    ) -- sudo apt-get install --reinstall --
  

• If there are packages among them that weren't installed from a package repository but manually from a Deb package file, apt-get will complain that it can't find those particular packages and you'll have to install them anew.