Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am trying to use proxoid (a proxy server to allow tethering like facility for mobile phones). This guide says that I need to restart the process udev similar to (in Ubuntu):

sudo /etc/init.d/udev restart

lsusb does list the mobile phone but I do not see a running process or a binary named as udev. There is a process udevd on CentOS /sbin/udevd. Is it the same as udev? I could not find specific information to CentOS as the centos.org site seems to be down for several hours now.

share|improve this question

Those instructions aren't very good. Udev automatically detects changes to the rules files in normal circumstances, you don't need to restart it after changing or adding a file in /etc/udev/rules.d. On the other hand, the rules are applied when a device is plugged in: if you change the rules, it doesn't affect devices that are already connected. The instructions are telling you to restart the udev subsystem to apply the new rules.

If you already know the rules you want to add, add them first, then plug your device in. If you do things in that order, you don't need to do anything else.

You may need to first plug in your phone to find its vendor ID, then write a rule accordingly. If so, the easiest way to apply your changes is to unplug your phone and plug it back in after you've added the rule. Alternatively, to reapply the rules for a particular device, run

udevadm --trigger --attr-match=idVendor=xxxx

where xxxx is your phone's vendor ID.

See also How to reload udev rules without reboot?

share|improve this answer

udev is very much integrated into modern Linux systems, there should be nothing to install or run.

share|improve this answer
It seems to me you did not bother to read the question properly? It was not asking about how to install udev (which does have installed/uninstallable/reinstallable userland components such as udevd), it was asking about how to restart the udev service which is a pretty normal straightforward thing for which there are normal straightforward commands. – goldilocks Mar 4 '13 at 12:41
...to be fair I just noticed the title of the question did include the word "Installing". Still, a quick read might have made this clear (?) – goldilocks Mar 4 '13 at 13:13
@goldilocks Udev notices changes to its configuration directories through inotify (I think even CentOS 5 is not so ancient as to predate that). The only time you'd restart udev is when upgrading it. – Gilles Mar 4 '13 at 22:58
@Gilles : Yes -- I addressed that (implicitly) in my answer (see "However"). The issue here is not mine, it's from the google code doc the OP is consulting (might help to actually: read the original post, read the link the post refers to, read my answer). I'm not saying vonbrand is wrong, just that his/her answer is not particularly informative or helpful. – goldilocks Mar 5 '13 at 1:32
@goldilocks Your answer is correct but mostly irrelevant. The problem is not to re-read the rules file, that happens automatically. The problem is to apply the new rules. See my answer. – Gilles Mar 5 '13 at 10:25

I need to restart the process udev similar to (in ubuntu) sudo /etc/init.d/udev restart

Actually those instructions do not use the term process and what you are referring to there a service, which is not quite the same thing. There probably is a udevd process running on centOS as part of the udev service, try:

ps -A | grep udev

In any case, if you want to restart the service, you should do it properly. If your centOS uses systemd:

systemctl list-units | grep udev

On fedora it's called systemd-udevd.service. You can leave the "service" off:

systemctl restart systemd-udevd

If it doesn't use systemd, try:

service --status-all | grep udev

Then if it's called udevd:

service udevd restart


I don't think you actually have to do that if you just want to load some rules. There's a chance you don't have to do anything (test that if you can) or:

udevadm control --reload-rules

Should do it.

share|improve this answer
Reloading the rules happens automatically. What you need to do is apply the new rules, either by plugging the device out and back in, or running udevadm trigger. – Gilles Mar 5 '13 at 10:26

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.