Udev is a Linux process that manages device file entries under /dev

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43
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How to reload udev rules without reboot?

How should one reload udev rules, so that newly created one can function? I'm running Arch Linux, and I don't have a udevstart command here. Also checked /etc/rc.d, no udev service there.
34
votes
3answers
4k views

Why are network interfaces not in /dev like other devices?

I'm mostly curious, but why aren't network interfaces in /dev? Are there any other kinds of devices that aren't represented as a node under /dev?
31
votes
5answers
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How can I detect when a monitor is plugged in or unplugged?

Is there any event that is triggered when I plug in or out an external monitor into the DisplayPort of my laptop? ACPID and UDEV don't react at all. I'm using onboard graphics on an intel chip. Here ...
30
votes
9answers
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A tool for automatically applying RandR configuration when external display is plugged in

is there a tool which enables one to: remember current RandR configuration (position, orientation, resolution etc) on per-monitor basis, automatically apply last known good configuration as soon as ...
25
votes
2answers
3k views

Why do some Linux distributions still have /dev/ttyS0, ttyS1, etc., even though newer computers don't have such a serial port?

Many new laptop and desktop computers do not have 9-pin/25-pin serial ports. Why do many Linux distributions still contain /dev/ttyS0, dev/ttyS1 device files? Since udev can create the device files ...
20
votes
1answer
12k views

How to assign USB driver to device

This question is two-fold: First, how do you manually detach a driver from a USB device and attach a different one? For example, I have a device that when connected automatically uses the ...
18
votes
2answers
16k views

How to run custom scripts upon USB device plug-in?

What is the state-of-the-art method for automatically executing custom scripts upon USB device plug-in under current Linux distributions like Debian/CentOS/Fedora? For example if you want to ...
11
votes
2answers
6k views

How can I find available network interfaces?

This is in regard to linux, but if anyone knows of a general *nix method that would be good. I booted a system yesterday with an ethernet cable plugged in. "NetworkManager" is not installed, so once ...
11
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3answers
628 views

Are there alternatives to using `udev`?

While I understand the greatness of udev and appreciate the developers' effort, I was simply wondering if there is an alternative to it. For instance, I might imagine there should be a way to make ...
11
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2answers
7k views

In which log should I check for udev errors?

I've written a udev rule which is run each time my device is mounted/dismounted. However, in which Linux (Debian) error log should I check when debugging such rules?
10
votes
5answers
757 views

Difference between sdX and vdX

When I use Ubuntu and CentOS, I see /dev/sda and /dev/vda. So I can't understand what is the different between above two?
10
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1answer
6k views

Understand output of `udevadm info -a -n /dev/sdb`

I plug an external HDD into my laptop. I try to find out the information by $ udevadm info -a -n /dev/sdb Udevadm info starts with the device specified by the devpath and then walks up the chain of ...
9
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3answers
2k views

Fake serial number of USB device

I have a mobile phone connected to my PC via USB. When viewing the device info using sudo udevadm info --attribute-walk the product and vendor id's show up fine, but there is no ATTR{serial}. An ...
8
votes
2answers
671 views

What's the difference between udev and hald?

I'm just beginning to dive into the internals of Linux, and I was wondering what the difference is between udev and the hal daemon. From what I gather, both seem to be responsible for managing hot ...
7
votes
2answers
2k views

How can I hide messages of udev?

When I plug in a usbhub (7 sticks in) udev displays a lot of messages in console. Can I hide these messages or send them to /dev/null?
7
votes
3answers
756 views

Udev- How do I find out which subsystem a device belongs to?

For example, I have device /dev/sdb. How do I find out it's udev subsystem?
7
votes
1answer
1k views

USB connect/disconnect notification

I use Linux Mint 13 MATE, and I'm trying to set up notifications when I plug/unplug devices. First of all, I found udev-notify package, but unfortunately it almost doesn't work for me: it works for ...
7
votes
2answers
2k views

Auto-run script when Wifi card is plugged in (udev)

I've been trying to use udev to make a Debian system run a bash script when a wireless card is connected. So far I created this file /etc/udev/rules.d/wifi-detect.rules: ACTION=="add", ...
7
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1answer
1k views

Suggestions needed for udev, udisks, autofs, notification setup for a complete automounting solution on Linux

Continuing on Automounting plugged devices in linux, which left things a bit basic. Running Gentoo, I'm automounting a combination of local and network devices on my laptop with autofs-5.0.4-r5. Doing ...
7
votes
1answer
379 views

How to enable “Predictable Network Interface Names”?

I decided to check out what name my ethernet device will end up with, but contrary to other distros, Debian doesn't seem to have activated this change (or is holding it back?), * Keep the old ...
6
votes
1answer
2k views

Difference between /dev and /sys/class?

What is the difference between the device representation in /dev between the one in /sys/class? Is one prefered over the other? Is there something one offers and the other doesn't?
6
votes
2answers
174 views

/dev/disk/ lists disks, why /dev/net/ doesn't list network interfaces? [duplicate]

I know that udev manages devices in /dev and I expected to find information about available network cards (hardware) or at least network interfaces (software) there. ifconfig output shows me eth0 and ...
6
votes
1answer
3k views

Why doesn't this udev rule trigger upon removal of the device?

I have two mice, one which has an issue where the middle mouse button and button6 get triggered simultaneously. So I configured my ~/.Xmodmap to disable this button. At the same time, however, I ...
6
votes
2answers
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mknod permanent in archlinux

I have a custom kernel module (on ArchLinux) that I can load manually and interact with. What I would like to do is have it loaded at boot time. So far I have managed to get the device appear in ...
6
votes
3answers
57 views

different passwords depending on plugged-in devices

I would like to have different passwords for my account(s): When (e.g.) a certain USB stick is plugged in then an easy password is to be used. The idea is: If I leave my computer then I take the stick ...
6
votes
2answers
2k views

Making UDEV ignore certain devices during boot.

I'm trying to make UDEV stop mounting one of my devices at boot time, and I've created a rule in /etc/udev/rules.d/ called 1-myblacklist.rules. All the rule does is matches the device by kernel ...
6
votes
1answer
380 views

trigger udev rules from systemd

I have one of those hdds, that have a very aggressive power management. To prevent load cycles from rising in to critical numbers I wrote an udev rule: SUBSYSTEM=="block", SUBSYSTEMS=="scsi", ...
6
votes
2answers
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Udev : renaming my network interface

I just installed RHEL 6.3 on a Dell 1950 server. This server as two GBit ports, Gb0 and Gb1. For some obscure reason, udev chose to name Gb0 eth1 and Gb1 eth0. This is definitly not a good find for ...
5
votes
3answers
4k views

How can I create a udev rule to mount a USB drive read only?

I'm trying to set a particular USB drive to always mount read only. If I plug it in, it is seen as sdb with a single partition, sdb1. Here are some relevant udevadm lines (not the entire output of ...
5
votes
3answers
1k views

Watch USB connections vendor id, product id, revision

I'd like to simply watch all devices added and removed from my system and view their USB vendor ID, product ID, and revision and other relevant information. How can I do this in Linux? Is there a ...
5
votes
2answers
3k views

Permanently changing the ownership (or group) of LVM volume

How can I permanently change the ownership (or at least the group) of a LVM volume? I figured that I have to use udev, but I don't know how the rule should look like? Let's say I want to change the ...
5
votes
1answer
3k views

Udev rule is not being used?

I'm setting up udev to handle my external USB hard drive when it gets plugged in and removed (no mounting yet). So far, I've made two new rules in /etc/udev/rules.d/10-local.rules to log ...
5
votes
2answers
127 views

Where to install local software that runs before /usr is available?

I'm writing a local program to be called by a udev IMPORT{program} rule. Normally, I'd install local software in /usr/local, but these udev rules are run when block devices appear. So they're running ...
5
votes
1answer
999 views

What is the correct way to write a udev rule to stop a service under systemd

I'm running Arch Linux, and I have a udev rule which starts a service when a device is inserted. In this case, it dials a connection when a 3G modem is plugged in. KERNEL=="ttyUSB*", ...
5
votes
1answer
1k views

udev rule for assigning known symlinks for identical usb serial devices

I have two (and possibly in the future, more) USB serial devices which are identical (down to the serial number, unfortunately) - they're actually BTC miners. Currently they end up as ttyUSBX where X ...
5
votes
1answer
399 views

Swapping <esc> and <caps lock> in a way that persists with external keyboards

I have a file called ~/.speedswapper which contains the following: ! Swap caps lock and escape remove Lock = Caps_Lock keysym Escape = Caps_Lock keysym Caps_Lock = Escape add Lock = Caps_Lock ...
5
votes
5answers
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Ubuntu 13.04 does not recognize USB drive

Using Ubuntu 13.04 (with Gnome 3), my new USB stick (details see dmesg/lsusb) doesn't show up automatically. Situation: The drive does not show up at fdisk -l The drive does appear when running ...
5
votes
1answer
2k views

How do I disable udevd in systemd?

I'm trying to boot a Fedora Rawhide LXC container from a Fedora 16 host, and it's not working - systemd just keeps dropping into emergency mode. Because udevd doesn't work in LXC containers, I thought ...
4
votes
3answers
902 views

Get device node by major/minor numbers pair

Each device node under /dev has its own major/minor number pair. I know that we can retrieve this pair of numbers from the device node by means of stat, like this: stat -c 'major: %t minor: %T' ...
4
votes
3answers
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Automounting USB sticks on Debian

I'm running Debian Squeeze on a plug computer (so SSH only, no GUI) and what I'm trying to do is get it so that when a USB stick is plugged in, it gets automatically mounted. What I've done is ...
4
votes
3answers
2k views

Why is pcmanfm such a headache when it comes to mounting filesystems?

If I would have known how much 'customization' it takes to get LXDE and its default file manager, pcmanfm, just working, I would probably have never chosen to try it. I've got a problem. Lots of ...
4
votes
4answers
3k views

UDEV rule when USB flash drive is unplugged

I wrote a rule to automount my USB stick to certain folder but when I unplug it the folder still mounted and when I ls there I see a lot of errors like: Directory bread (block: NNNN) failed I tried ...
4
votes
1answer
2k views

Preventing mounting some partition by user (gnome+udisk)

I'd like to prevent automounting one partition (known UUID etc. ) on one external harddrive. Others should be automounted. Distro is 'modern' (uses lots of beta software) and uses udisk+udev for ...
4
votes
1answer
984 views

can not create /dev/shm

I need to create /dev/shm on an embedded ARM system. From "Installed The Latest Changes to Current and......". I see that it can be created with mkdir /lib/udev/devices/shm, but I'm wondering what ...
4
votes
2answers
551 views

Disable the external keyboard from a script

I have a udev rule for my external keyboard. I can catch events, and by running a script I can also reach udev env variables. Can I disable keyboard with udev? Or must I use a script to disable the ...
4
votes
1answer
1k views

How does udev create /dev/sr*? (Or: Which rule does create /dev/sr*?)

udev is responsible for populating /dev. It adds and removes device nodes to /dev dynamically based on rules/configs/scripts under /lib/udev and /etc/udev/. If I have a CDROM device node /dev/sr0 I ...
4
votes
1answer
53 views

how to write a udev rule to remove a tag?

Is it possible to write a new udev rule that undoes TAG+="uaccess" (removes the uaccess tag) without undoing any of the other tags on a device? If so, how? (I have a device that should be opened by ...
4
votes
2answers
559 views

How does udev get device numbers for the devices it creates?

Spun off from a small exchange in chat. One of the primary advantages of udev is that you don't have to worry about major and minor device number exhaustion anymore. But the devices created by udev ...
4
votes
2answers
2k views

udev rules don't appear to be working

I'm running Arch Linux on my server, and I need to let users of the group usb access my weather station. Here's my rule: /etc/udev/rules.d/usb-70.rules SYSFS {idVendor} == "1941", SYSFS {idProduct} ...
4
votes
2answers
975 views

Auto-mounting to a directory other than /media in Fedora 13

I am using Fedora 13. I need to be able to configure how media are mounted automatically. For an example, I want to change the parent of all mounted media to be a directory other than /media. All the ...