Questions tagged [dev]

The Linux/Unix /dev directory contains the special device files for all the devices.

Filter by
Sorted by
Tagged with
0 votes
0 answers
48 views

How can I find out what's changing the group for /dev/ttyUSB*, Ubuntu 22.04.3 LTS

I've got a couple of USB devices that suddenly stopped working a few hours ago after several years of working fine and at least a week since I last touched the machine they were on. After a bit of ...
Dave's user avatar
  • 101
0 votes
1 answer
40 views

Messed up with /dev/tty* ownership

I was flashing a Flipper Zero Wifi Dev Board and I needed to have /dev/ttyACM0 owned by dialout group... The thing is now I have tried to revert the stuff, making a chown root:tty /dev/tty*, and chmod ...
DaniWein's user avatar
0 votes
2 answers
45 views

My 64gig SD card thinks its 32gig

so I cloned my 32-gig emmc into my 64-gig SD card with the "dd" command. The only problem is that it thinks it has 32 gigs of total storage... Does anyone know how to "convince" (...
mollinas's user avatar
0 votes
1 answer
359 views

Created new Fedora 37 VM with 1 TB but df shows 15 GB

This morning, I created a virtual machine with 1 TB of storage through VMware, I verified on initial install that the 1TB disk was selected and ran the installation, went through the initial ...
RussianLinuxGuy's user avatar
0 votes
1 answer
239 views

linux + how to convert disk DEV name to humane reading

we get from site remote machine the files under /var/log/sa/* and we copy all them on our local machine under /var/tmp/sa/* so when we run sar -f /var/tmp/sa/sa14 -d on our local machine we get the ...
King David's user avatar
2 votes
1 answer
169 views

list of files (ls /dev) is different when run on command line vs. via crontab

Why can't cron ls certain files in /dev using my script ? The script can list /dev completely when run from the command line. The same script run from either cron setup cannot see (list, ls) most of ...
David Purdy's user avatar
0 votes
1 answer
116 views

VirtualBox createvm in Dockerfile fails

I'm trying to create a Dockerfile that has a VirtualBox VM inside: it's based on ubuntu20.04 and I first install and setup the packages: FROM ubuntu:20.04 ... RUN echo 'debconf debconf/frontend select ...
alle_meije's user avatar
12 votes
1 answer
5k views

Shouldn't my machine have a /dev/ram0 file?

I have a college assignment where I have to create a RAM Disk. I have been told to then make a C program that writes multiple times on a file placed inside the RAM Disk and then do the same on a file ...
ferranad's user avatar
  • 131
-1 votes
1 answer
2k views

Where is my MMC device?

I'm performance testing an MMC to failure and would like to use tools like smartmon-tools and mmc-utils to check drive health as I write data. I'm stuck since I can't find the device path of my MMC. ...
Scott S's user avatar
  • 101
4 votes
1 answer
10k views

Get device info for dev file

This is a very simply question. I have 3 potential camera devices in /dev/: video0, video1 and video2. I need to find out which one is my actual webcam and which one is a loopback device. I couldn't ...
sonofevil's user avatar
  • 117
0 votes
1 answer
1k views

move hard-drive from /dev/sdb1 to /dev/sdc1

During a backup procedure in a bash script, I should remount a hard-drive mounted on dev/sdb1 onto dev/sdc1. I am able to umount /dev/sdb1, but then I loose track of the device. After shutting down ...
Marcel Sonderegger's user avatar
1 vote
2 answers
456 views

Writing to /dev/sdX instead of /dev/sdX1

What happens physically if I want to copy some files to an external hard drive and do cp -a [file] /dev/sdX instead of cp -a [file] /dev/sdX1? Or when wiping a drive by overwriting it with zeros, is ...
david's user avatar
  • 337
0 votes
1 answer
3k views

/dev/ttyACM0 lost after sleep - How to redetect / restart / rescan for ttyACM0?

I have a Ubuntu 16.04 based VM which runs inside VirtualBox on Windows 10. On my Host, I've connected a ZWave USB antenna, which I've then mapped/attached to the VM. When I first boot my VM, I can ...
Eric B.'s user avatar
  • 1,021
3 votes
0 answers
845 views

Finding .npm debug logs in Azure DevOps Pipeline

I have an existing build pipeline for a Vue web app that has worked flawlessly for over a year now up until today. I'm not a devops guy so I don't understand it 100% and got thrown into this, but here ...
CLosee's user avatar
  • 31
4 votes
1 answer
2k views

What is the difference between "mount -t ..." and "mount -o bind ..." with regard to chroot environment

So I am setting up a chroot where I need proc, sys and dev folders. I have read that I need to mount them as follows: mount -t proc /proc /mnt/chroot/proc mount -t sysfs /sys /mnt/chroot/sys mount -...
code_fodder's user avatar
  • 1,561
0 votes
1 answer
276 views

Consistent USB device adapter naming on Linux

I have a USB port into which I insert all sorts of different USB disks over time. The kernel does not consistently allocate the same device for it, so I have to go hunt after each insert. How can I ...
Johannes Ernst's user avatar
0 votes
1 answer
235 views

USB Drive not recognized under /dev

I was reading/learning about partitioning, creating file-system, etc. and wanted to do some practical. So i booted my CentOS installed on my windows laptop using Virtual Box and inserted a blank usb ...
LoveWithMaths's user avatar
1 vote
2 answers
2k views

Running 'cat /dev/urandom > /dev/audio' does nothing

I am trying to have some fun by playing some random audio using /dev/audio under Ubuntu 17.10. The command cat /dev/urandom > /dev/audio executes successfully but it outputs absolutely nothing to ...
Safal Aryal's user avatar
0 votes
1 answer
84 views

Detected devices name

I am using the Barebox bootloader to boot into an embedded system. I am wondering why some SD-card of mine shows up as 2 devices /dev/disk0.0 /dev/disk0 And sometimes another SD card it shows only ...
GeneCode's user avatar
  • 373
3 votes
2 answers
5k views

Linux, GSM, nmcli - working with two GSM Modems and connections

I have a following situation. I have two USB modems (one Huwawei LTE modem, one ZTE 3G modem) with two different SIM cards from two different providers (orange and play to be specific). Using ...
Paweł Sopel's user avatar
3 votes
1 answer
8k views

Device /dev/spidev* not found

I have a Banana Pi M1 and wanted to flash libreboot on a ThinkPad T400. I followed Raspberry Pi (ThinkPad X200), as RPi's GPIO pins are almost the same as BPi's and T400's chip is the same as X200. ...
Megver83's user avatar
  • 257
1 vote
2 answers
4k views

how do I figure out where a usb controller is in /dev?

This is a linux question, how do I figure out where a usb controller is in /dev? I have tried doing ls /dev > before.txt ls /dev > after.txt diff before.txt after.txt pluging the device in when ...
j0h's user avatar
  • 1,460
1 vote
1 answer
5k views

How to clear /dev/dm-0

I noticed /dev/dm-0 is using almost all my HDD space: $ df -h [...] /dev/dm-0 227G 207G 8,8G 96% / [...] I believe /dev/dm-0 is some kind of cache for mounted filesystem (It is the ...
ppr's user avatar
  • 143
2 votes
1 answer
179 views

dd aplied to dev USB before connect corrupt /dev/sdX and dont work

I have a USB where I'm coping an ISO of 5 Mb aprox with a small OS with its own grub. If I connect the device and check it sudo fdisk -l I get: ... Device Boot Start End Sectors Size Id Type /...
vgonisanz's user avatar
  • 145
1 vote
2 answers
1k views

How to Access `/dev` From Inside a `chroot` Jail?

     How can one access /dev from within a chroot jail? I'd like to know how to do this on OS X v10.11.5 'El Capitan,' in particular. I've already tried to create an ...
RandomDSdevel's user avatar
0 votes
1 answer
218 views

Attached devices change /dev/sd value

I have a script which auto mounts my Windows partition based on UUID, reason: my attached devices change their /dev/sd value. After booting up, my external hard drive might take on /dev/sda or /dev/...
CybeX's user avatar
  • 1,385
0 votes
1 answer
429 views

How can I get a Git repo to push/pull when the Git server is behind a firewall?

My work place currently has a gitlab server behind their corporate firewall and currently their public dev sites are facing the internet. I can access the gitlab server only when I'm on their vpn. I ...
Patoshi パトシ's user avatar
1 vote
1 answer
2k views

Detecting new USB devices with bash?

I'm writing a bash script that needs to detect when a usb storage device is inserted and assign it to a variable that would otherwise, typically look something like: usb=/dev/sdb. I have a few ...
voices's user avatar
  • 2,731
1 vote
0 answers
613 views

How can I set device mode via networkd

How can I set mode to device (for example monitor/ap to wlan) via networkd deamon in .link file ??? Because I want to set bridge in .network of wlan device and I can't do it until I set it in ...
ceph3us's user avatar
  • 125
2 votes
2 answers
8k views

v4l2 Identifying /dev/video* via lsusb

I'm writing a script that must use a particular camera plugged in to my system. $ lsusb|grep C930e Bus 001 Device 011: ID 046d:0843 Logitech, Inc. Webcam C930e How can one programatically discover ...
lysdexia's user avatar
  • 169
1 vote
0 answers
481 views

creating linux device files for bootstrap

I'm currently independently researching device files as a part of learning more about the Linux system in depth. My current goal is to bootstrap Debian Linux through cdebootstrap. I followed the guide ...
cellsheet's user avatar
  • 111
1 vote
1 answer
1k views

rsyslog.conf: kern.err /dev/console. Where do these messages go?

There is a commented line in rsyslog.conf: #kern.* /dev/console If I add this line to the configuration file: kern.notice /dev/console Where do these messages go? If I run this ...
Sunshine's user avatar
  • 111
0 votes
0 answers
2k views

Why do loop devices sometimes refuse to go away?

I regularly mount the partitions inside an image file as loop devices: sudo kpartx -a test.img That creates loop devices such as /dev/mapper/loop0p1 /dev/mapper/loop0p2 When I'm done, I get rid of ...
Johannes Ernst's user avatar
1 vote
3 answers
901 views

Can the contents of /dev/disk0 (/dev/sda, etc) be used as stdin?

I'm learning about the /dev filesystem. I've begun with /dev/sd* (Linux) and /dev/disk* (OS X), and I've found some interesting behaviour. If I run: $ sudo xxd -l 1024 /dev/disk0 I get the following ...
Ephemera's user avatar
  • 1,381
1 vote
1 answer
965 views

Not quite grasping /dev/random and /dev/urandom

I am not quite understanding the difference between /dev/random and /dev/urandom on Linux systems. What does it mean to run out of “entropy” and how does the system get more? What does it mean when ...
user365967's user avatar
11 votes
2 answers
24k views

How is by-id created on Linux?

Sticking a USB-microcontroller on the port (similar to Arduino) creates these two files: /dev/serial/by-id/usb-MBED_MBED_CMSIS-DAP_10105a42e87da33c103dccfb6bc235360a97-if01 /dev/disk/by-id/usb-...
Pithikos's user avatar
  • 1,634
0 votes
1 answer
84 views

Drive assignments changing

I have an Ubuntu 14.04 Server machine set up with 3 drives: Two 2TB HDDs, and a 4GB USB drive for system. It seems that every time I boot the system it changes what drives are assigned to /dev/sd(a/b/...
Jonah's user avatar
  • 642
-1 votes
1 answer
1k views

Micro SD impossible to modify (write or format)

Recently i had problems with my SD card used for my android device, basically i cannot modify it (write or format). Only read it, if i try format or write, any time that connect and fisconnect from ...
User1234552's user avatar
1 vote
1 answer
1k views

Cat to /dev/audio not working

I downloaded some files and am trying to cat them to /dev/audio (for fun of course, I'm sure I could just play them) and I guess this is supposed to work, but it doesn't? I get permission denied and ...
user341814's user avatar
0 votes
1 answer
2k views

Can't mount external HDD. Device listed at lsusb but doesn't appear at /dev

Device works at Windows but doesn't appear at /dev. How can I mount it? So let's go to the infos... uname -a: Linux deeptought 3.13.0-30-generic #54-Ubuntu SMP Mon Jun 9 22:45:01 UTC 2014 x86_64 ...
marcelhb's user avatar
1 vote
2 answers
2k views

/dev/dsp missing in debian and cannot hear festival utterance

Tried to make an utterance in festival and it seems /dev/dsp/ is missing in the debian. How to add this? festival> (SayText "Hello") Linux: can't open /dev/dsp #<Utterance 0xb669c708>
pirateknight's user avatar
0 votes
1 answer
235 views

Can't recongnize my SSD device file in /dev

I am using Ubuntu and can't find my SSD device file. The /dev directory has following contents: agpgart audio audio1 audio2 audio3 audioctl char console core dsp dsp1 dsp2 dsp3 fd full kmem kmsg log ...
Ashish's user avatar
  • 3
0 votes
2 answers
375 views

Why does the /dev directory exist?

In Linux, there is the /dev directory, which is a special directory which contains all of the files for devices and other things like random, urandom, etc. Why did this directory exist? Was it just ...
Justine Krejcha's user avatar
0 votes
1 answer
610 views

Does unplugging a disk from linux change disk name after restart?

I had 5 disks (sda, sdb, sdc, sdd, sde) sda is being used for root and boot. sdc,sdd and sde disks are being used by lvm. We unmounted and unplugged the sdb, now I need to restart the server. I am ...
ramazan polat's user avatar
1 vote
1 answer
591 views

Hauppauge HD PVR 2 to ffmpeg on OS X

How can I use ffmpeg to capture video and audio from a Hauppauge HD PVR 2 connected to my Mac via USB? I have seen a couple posts here and here about doing this on a Unix machine (not OS X) using ...
tboyce12's user avatar
  • 173
1 vote
1 answer
4k views

Disable device node using udev (/dev/sr0)

I am trying to disable udev from generating /dev/sr0 device (my cdrom) and Im trying to write udev rules. I added a file 10-cd-trial.rules in /etc/udev/rules.d and /lib/udev/rules.d, the contents are:...
Vigneshwaren's user avatar
16 votes
5 answers
93k views

Partition Not Showing up in /dev

I recently unmounted a 4TB hard drive from one computer in order to access the files directly from another computer. It seemed like there were no problems with the unmounting process. When ...
rmsrms1987's user avatar
0 votes
2 answers
277 views

How to move /dev/random to another drive on a server

We found a bottleneck in our server (hosted on HDD) related to the /dev/random function. We want to have the OS use the /dev/random that is on our SSD drive rather than the HDD. How can we have the ...
d-_-b's user avatar
  • 325
21 votes
3 answers
29k views

Why does `cat /dev/urandom` break your terminal?

In reference to this question: https://serverfault.com/questions/534449 How does cat /dev/urandom make some terminal emulators go wonky?
Christian Chapman's user avatar
162 votes
7 answers
93k views

Why is “/dev/rdisk” about 20 times faster than “/dev/disk” in Mac OS X

According to the rasbery pi documentation, You can load your OS to a flash card with either /dev/disk or /dev/rdisk. rdisk stands for raw disk. /dev/disk is a block level device, why would rdisk ...
spuder's user avatar
  • 9,965