How to update Linux "locate" cache

How can I update the cache / index of locate? I installed new packages and the files are clearly not yet indexed.
So which command do I have to commit, in order for the indexer to trigger?

I’m currently working on debian jessie (testing):
with Linux mbpc 3.13-1-amd64 #1 SMP Debian 3.13.7-1 (2014-03-25) x86_64 GNU/Linux

Asked By: sweisgerber.dev

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The command is:

sudo updatedb

See man updatedb for more details.

Answered By: pehrs

On OSX this is: sudo /usr/libexec/locate.updatedb

Which can be linked with: sudo ln -s /usr/libexec/locate.updatedb /usr/local/bin/updatedb

Seems silly to have to make a symbolic link for a standard unix command, but there it is.

Answered By: jcollum

While the answer:

sudo updatedb

is technically correct, it is almost never a good idea to run updatedb on a command line by itself, if there is also a cron job installed. Depending on the Unix flavor the cronjob contains locking provisions and any amount of configuration which is not covered by the standalone updatedb command.

If the locate database needs to be updated frequently, it is definitely worth the effort to determine the proper cron job for a specific host and run it manually.

Depending on the administrator, the cronjob for updatedb may be hidden in various locations. So a simple brute-force attempt to find the cron job would be:

( sudo crontab -l > /tmp/crontab.root;
  ( echo /tmp/crontab.root; ls -1d /etc/*cron* /etc/*cron*/* ) 
  | tr 'n' '' 
  | xargs -0 -r -e grep -nH -e updatedb;
  rm -f /tmp/crontab.root
) 2>/dev/null

which shows the following result on one of my Ubuntu systems:

/etc/cron.daily/mlocate:5:[ -x /usr/bin/updatedb.mlocate ] || exit 0
/etc/cron.daily/mlocate:21:flock --nonblock /run/mlocate.daily.lock $IONICE /usr/bin/updatedb.mlocate

The correct command to update the locate database in this case is therefore

sudo /etc/cron.daily/mlocate

A more systematic approach is to determine the package which provides locate and updatedb.

E.g., on an OS with apt/dpkg packaging you can find which flavor of locate is installed with:

dpkg -S locate | grep /bin/

In my case it is:

mlocate: /usr/bin/updatedb.mlocate

To see, which cron job if any is responsible, run:

dpkg -L mlocate | grep cron

Which in my case shows:

/etc/cron.daily
/etc/cron.daily/mlocate

To update the database, run the cron job as root:

sudo /etc/cron.daily/mlocate

If there is no cronjob, and updatedb by itself does not work, try finding your installed flavor with:

dpkg -L mlocate | grep /bin/

which returns:

/usr/bin/mlocate
/usr/bin/updatedb.mlocate

Update

There is yet another approach to run updatedb on a daily basis using a oneshot systemd service named updatedb.service, mlocate-updatedb.service, etc. This service is triggered by a corresponding timer updatedb.timer, mlocate-updatedb.timer. Here is a sample service file, I found in a repository:

[Service]
Type=oneshot
ExecStart=/usr/bin/updatedb
IOSchedulingClass=idle

Although it just calls ionice -c 3 /usr/bin/updatedb in this case, it still is better to start the service, making sure it is run in the correct environment without the need to double and triple check the service file for changes introduced by the system maintainers during updates:

sudo systemctl start updatedb.service

Besides examining the package file list, checking for a service can be done with a command like:

systemctl list-unit-files | grep 'updatedb|locate'
Answered By: wolfmanx

The "locate" package usually comes with a cronjob which runs on a daily basis and updates the locate database.

You can run the cronjob manually to enforce an update of the locate database.

On Debian, you can do this:

sudo /etc/cron.daily/locate

Note that this can run a while, depending on the system performance and the amount of files to scan.

Answered By: thomas.schuerger
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