‘locate’ on ubuntu with an encrypted home dir

free software,geeky,linux,ubuntu — 5. Oct 2011

recently, i noticed that the locate command on my ubuntu system didn’t work as expected. it simply didn’t list files located in my $HOME dir, while it did still list files in the system directories. it took me a while to figure out that this behaviour was due to the fact that i decided to check the “encrypt home dir” option when i last (re-)installed the OS.

on second thought, it makes sense that it works that way, since the command to update locate‘s database (updatedb.mlocate on ubuntu) is run as a root cronjob, and as such it can’t access the filesystem while it’s encrypted. on the other hand, understanding this requires quite a bit of prior knowledge about how locate works, and i think it’s a bit rough to let the users figure this out all by themselves, without as much as a warning. the situation would be much improved if locate would at least spit out a warning that it can’t access the home dir, instead of the ominous silence, from which we usually conclude that no matching files exist on the disk.

after some googling, i found a good solution for this problem. this guide explains how to set up locate to store a separate, user-specific database inside the encrypted home directory. this also requires a user-specific cronjob. after following that guide, locate once again works just as expected on my system.