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9
votes
4answers
4k views

If I connect a physical device, how can I ever know which device file belongs to it?

Say I plug in several USB drives which don't get automatically mounted. How can I find out which device file belongs to which physical device, so I can mount it for example? I'm running Mac OS X but ...
2
votes
2answers
32 views

Check if a drive has been Zeroed with xxd and uniq?

I'm looking for a way to check if the entire binary contents of a USB device are purely 0s. I'm trying this command: sudo xxd /dev/sdb | uniq but it has no output and just runs forever. I've ...
8
votes
2answers
209 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 ...
6
votes
2answers
3k views

How does cat know the baud rate of the serial port?

I regularly use cat to view debugging information in the console from my FPGA development board over the serial connection, but I never have had to tell linux what the baud rate is. How does cat know ...
7
votes
1answer
44 views

How to find which serial port is in use?

The Question: I plugged in a device (i.e. GSM modem) through a serial port (a.k.a. RS-232), and I need to see with which file in /dev/ filesystem this device was tied up, to be able to communicate ...
2
votes
1answer
764 views

Debian USB automount

Got my USB flash automount broken after reboot. Using Debian 6, GNOME 2 My NTFS hard disk is still mounting correctly. When i connect my Android smartphone (with SD and local drive) my messages log ...
1
vote
1answer
492 views

Can I use a parallel port as a CUPS input device?

I have an old piece of a hardware that does diagnostics on medical equipment. It prints out results over a parallel port. Is there any way to have CUPS accept jobs from a parallel port and redirect ...
48
votes
18answers
118k views

How do I find out what hard disks are in the system?

I need to know what hard disks are available, including ones that aren't mounted and possibly aren't formatted. I can't find them in dmesg or /var/log/messages (too much to scroll through). I'm hoping ...
0
votes
2answers
30 views

Can I change devices permissions with chmod?

Before read: I don't want to use any udev rule. I need to change (programmatically) the permissions of some device. But first in order to underestand what I have to do (in code) I want to make the ...
2
votes
0answers
33 views

Debian - cannot find cdrom

Having a jessie/sid debian box on kernel 3.13 (had same issue on kernel 3.10) First thing I notices was that k3b didn't find any optical drives. Then: The optical drives (dvd-writers) are found in ...
3
votes
1answer
29 views

How to get address of connected USB modem?

I just connected my N81 telephone as USB modem to Linux Mint 14. All works fine, just wondering how to find a full path to this device, something like /dev/tty*.
1
vote
1answer
28 views

Why does RTC device have 254,0 instead of 10,135 as Major,Minor numbers?

Why isn't /dev/rtc the well known "c 10 135" device that it's on x86, but a magic undocumented "c 254 0" device? Devices.txt lists this major number as LOCAL/EXPERIMENTAL USE. I'm working on a ...
5
votes
1answer
102 views

Why does “cat ttyUSB0” not produce output?

I connected an infrared receiver to a USB port ... (the last line of dmesg tells device file) $ dmesg [10496.596063] usb 7-2: new full-speed USB device number 2 using uhci_hcd [10496.751112] usb 7-2: ...
2
votes
1answer
49 views

Is it possible to simulate/force/fake an USB device unplug and replug on Linux?

So I've got a strange problem that I've been running onto. I've got a bitcoin usb miner, Bitfury, and I'm using CGMiner to mine. When I start the application, as root, the USB device is not detected ...
0
votes
0answers
27 views

Editing a device tree to disable driver loading

Below is a section of device tree. ps7_ethernet_0: ps7-ethernet@e000b000 { #address-cells = <1>; #size-cells = <0>; ...
2
votes
1answer
487 views

Unable to use busybox implementation of hwclock

I have a buildroot generated kernel (3.6.11) and root file system running on an x86 device. It uses busybox and I am trying to set the BIOS hardware clock using hwclock. I get this error whenever I ...
3
votes
1answer
276 views

How creation of new USB device file in /dev/bus/usb/001/ directory work?

I noticed that every time I connect a USB device, a new device gets created in the /dev/bus/usb/001/ directory. Further on each reconnection of the same device, the "Device Number" and "ID" change. ...
2
votes
0answers
19 views

What are the two values in < > in a device tree .dts file ?

Following is the code snippet in a device tree file: flash@0 { compatible = "n25q128"; reg = <0x0>; spi-max-frequency = <50000000>; ...
2
votes
1answer
213 views

Udev rule to match multiple node USB device

I have a 3G/GPS device that creates 5 tty nodes, although it's only one physical USB connection. Basically, a multi port usb-serial adapter. I'm trying to create some udev rules to make sure those ...
1
vote
0answers
49 views

Why is my embedded Linux unable to detect the sd device?

I have this ARM9 SAM9G25 embedded System, running a Linux 2.6.39 Kernel and a Busybox. I put the Images (of the bootloaders, and the linux+initramfs) on a SD so that in the end the system is booting ...
3
votes
1answer
88 views

Is there a way to change device names in /dev directory?

I wrote this rule for testing purpose: SUBSYSTEMS=="usb", ATTRS{manufacturer}=="Kingston", ATTRS{serial}=="001CC0EC34A2BB318709004B", ATTRS{idVendor}=="0951", ATTRS{idProduct}=="1642", ...
5
votes
3answers
845 views

Mounting a device — role of /dev, /media and /mnt, and the mount command [closed]

I have several closely related questions about what happens when I insert a CD. The files on the CD /media/Ubuntu\ 11.04\ i386/, but from what I've seen /dev/cdrom is also involved. What is the ...
4
votes
1answer
135 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?
3
votes
2answers
105 views

Unable to find root device / sda partitions missing

I have installed Archlinux, and after that GRUB. I manually entered menu entries for both my Windows and Arch installation. GRUB has no problems booting, and can successfully load in Windows. It ...
1
vote
2answers
27 views

What is a device tree and a device tree blob?

What exactly is a device tree, and a device tree blob? Where can I get its source code for a particular linux version? I found such name while running linux on xilinx chips (having ARM 9), for ...
4
votes
1answer
1k views

Writing /dev/random to file?

If you ran the following, what would happen? cat /dev/random > ~/randomFile # don't run Would it be written until the drive runs out of space, or would the system see a problem with this and ...
15
votes
3answers
807 views

mv a file to /dev/null breaks dev/null

If I do: touch file; mv file /dev/null as root, /dev/null disappears. ls -lad /dev/null results in no such file or directory. This breaks applications which depend on /dev/null like SSH and can be ...
0
votes
1answer
24 views

Confusion about group `cdrom` in linux system

When I type command groups ubuntu, the output would we like, ubuntu : ubuntu adm dialout cdrom floppy audio dip video plugdev netdev admin I am interested in the cdrom group. What does the group ...
1
vote
0answers
23 views

Execute command when mouse is pluged/unpluged on GNU/Linux

Is it possible to have something like event handler for plugging unpluggig a mouse in Unix System? I want to have a script that will enable/disable touchpad but not only on startup (you can find ...
6
votes
1answer
141 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 ...
2
votes
1answer
86 views

Map physical USB device path to the Bus/Device number returned by lsusb

I need to get the title of the attached USB device. I can do that with lsusb. udev allows some substitutions when I write rules: say, we can use $kernel to get name of the device, or $devpath to get ...
1
vote
0answers
64 views

Fedora unable to detect USB or wireless networks? [closed]

I installed Fedora(Gnome) 19 on a Dell Inspiron with Intel i3 processor, and a factory built-in Windows 7 home premium OS. The installation process completed successfully. But now when I log into ...
0
votes
0answers
184 views

How do I find out which process is using my V4L2 webcam?

I tried to run the following: $ vlc -I dummy v4l2:///dev/video0 --video-filter scene --no-audio --scene-path webcam.png --scene-prefix image_prefix --scene-format png vlc://quit --run-time=1 ...
1
vote
0answers
25 views

Mount partition with truecrypt using the commandline

I'm trying to mount a encrypted HDD with truecrypt, but I cann't find the device. Where can I finde my HDD and what is the command to mount it in truecrypt? I'm using Raspbian on Raspberypi.
0
votes
2answers
134 views

Allow non-root user to read/write /dev files

In my /dev folder, I would like the following files to be user readable and writable: /dev/ttyUSB0 /dev/gpib0 How do I do this without using chgrp? I can edit /etc/udev/rules.d but I do not know ...
1
vote
1answer
55 views

Getting message “Error trying to open /dev/dvd exclusively” at the end of a DVD burning process when using growisofs

I am using Linux Fedora Core 4 (have to work with a legacy system) and trying to burn DVDs as a non-root user using the growisofs utility. I seem to be getting this error message at the end of the ...
1
vote
1answer
22 views

Disable emulated scroll wheel (EmulateWheel) for specific programs

Is it possible to disable evdev's EmulateWheel option when using specific programs? In my use case, I would like to be able to interact with the Acme text editor and with some VMs using my Thinkpad's ...
0
votes
0answers
90 views

Debian 7.3 - Nautilus doesn't show devices and partitions in left panel after changing partitions

Today I changed some partitions (moving, resizing) on my second hard drive and after restarting Debian I noticed that Nautilus doesn't show either partitions nor removable devices in left panel. In ...
1
vote
1answer
40 views

Why does the SELinux filesystem have it's own null device?

Looking through /sys/fs/selinux, I found this: # ls -l /sys/fs/selinux/null crw-rw-rw-. 1 root root 1, 3 Jan 24 02:47 /sys/fs/selinux/null Which is identical to /dev/null: # ls -l /dev/null ...
1
vote
1answer
53 views

Permission of DVD device file not being retained when machine is rebooted

I am using Linux Fedora 4 and would like a non-root user to be able to write to DVDs using the DVD drive. I was able to do this by adding write access to the group of the device file /dev/scd0 and ...
1
vote
0answers
30 views

Create a fake read only device like file with incrond

I need to generate UUID with uuidgen (not through any function call, but external command, because processes which will read the file cannot call any APIs or external commands directly). My idea is ...
2
votes
1answer
114 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 ...
3
votes
1answer
90 views

USB device to be detected at the “same” /dev point always?

In Linux (actually I'm with CentOS v6.5), whenever I plug in my USB Terminal/Character Device (some kind of USB Adapter) for the first time (after booted), it is detected at: /dev/ttyUSB0 But ...
3
votes
1answer
544 views

Explain EV in /proc/bus/input/devices data

Can anybody explain to me what the EV value in /proc/bus/input/devices is? The keyboard always has value 120013. Why?
2
votes
1answer
47 views

What happens under the hood when some data is sent/received on an uart (or similar)?

I am trying to understand how computers work and I was thinking about peripherals. Here is what I understand so far but some parts are missing. Using an Arduino, I send some text every second (a then ...
4
votes
3answers
1k views

what is stored in /dev/pts files and Can we open those?

I am curious to know that what is stored in /dev/pts/ files . Can we open those files ? According to my knowledge /dev/pts files are created for ssh or telnet session .
3
votes
2answers
75 views

Is there a uniform way to discover information about devices?

UPD: Changed question title from manage devices to discover information about devices One of the frequent thing I do is look up info about devices on my systems. And I am constantly find myself ...
4
votes
1answer
5k views

/dev/sdb: No such file or directory (but /dev/sdb1 etc. exist)

I'm not sure what is wrong here but when running fdisk -l I don't get an output, and when running fdisk /dev/sdb # I get this fdisk: unable to open /dev/sdb: No such file or directory I'm ...
31
votes
3answers
2k 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?
0
votes
1answer
125 views

Using USB hub for keyboard and mouse in multiseat

I want to configure a 2 user multi-seat in Linux. Is it possible to configure keyboard and mouse for second seat with a USB hub on a single USB port or I need to connect each of them to a separate USB ...