Questions tagged [dev]

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

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13
votes
1answer
2k 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 ...
-1
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1answer
46 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. ...
0
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0answers
13 views

Cinder Volumes not permanent in DevStack

While testing an application in DevStack, I noticed that my environment would become corrupt after VM restarts and discovered it was because the instance volumes would disappear. Since Cinder is using ...
3
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1answer
259 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 ...
0
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0answers
14 views

Is there a way to release /dev/video0 from any usage?

I'm using flashplayer with fscommand. Flashplayer uses camera at the start of swf. lsof /dev/video0 gives me information that only flashplayer at the moment uses camera. So when I'm running scripts ...
0
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0answers
23 views

Graphic interface and get information from script bash

first of all I'm bad at web development so I have a question which might be funny but I need some advice in fact i created a menu under ubuntu which creates install and configures configuration ...
0
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1answer
111 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 ...
0
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0answers
15 views

Xe25QBB dev mode lockout

Obtained a chromebook 2nd hand. Has a lockout on devmode...need FWMP disabled to get to shell to make necessary changes to use the device. Have attempted to pull battery to get firmware access to no ...
1
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2answers
210 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 ...
0
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1answer
1k 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 ...
3
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0answers
439 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 ...
2
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1answer
1k 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 -...
0
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1answer
115 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 ...
0
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0answers
2k views

Merge with Jenkins using pipeline

I try to merge branch ( master <-- newBranch ) with Jenkinsfile (pull request trigger) without conflict. When the Jenkins finishes running I get an error message on step3: "fatal: There is no ...
0
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1answer
132 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 ...
1
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2answers
875 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 ...
0
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1answer
34 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 ...
3
votes
2answers
3k 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 ...
3
votes
1answer
6k 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. ...
0
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2answers
2k 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 ...
0
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1answer
3k 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 ...
1
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1answer
144 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 /...
1
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2answers
842 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 ...
0
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1answer
86 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/...
0
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1answer
288 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 ...
1
vote
1answer
1k 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 ...
1
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0answers
469 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 ...
1
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2answers
5k 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 ...
1
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0answers
361 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 ...
1
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1answer
838 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 ...
0
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0answers
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 ...
1
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3answers
790 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 ...
0
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1answer
711 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 ...
7
votes
2answers
16k 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-...
0
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1answer
78 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/...
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1answer
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 ...
1
vote
1answer
734 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 ...
0
votes
1answer
1k 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 ...
1
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2answers
1k 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>
0
votes
1answer
202 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 ...
0
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2answers
218 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 ...
0
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1answer
322 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 ...
1
vote
1answer
515 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 ...
0
votes
1answer
3k 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:...
16
votes
5answers
68k 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 ...
0
votes
2answers
212 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 ...
16
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3answers
23k 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?
150
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7answers
82k 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 ...
0
votes
1answer
192 views

What is /dev/blog?

I have tried searching for /dev/blog on google, duckduckgo, etc.; but I cannot find any information about it. I've also asked another sysadmin where I work, but he didn't know what it is used for ...
1
vote
1answer
1k views

Ubuntu Drive Mount Order

I have two drives, a 120GB SSD and a 2TB HD. I set the BIOS to boot from the SSD, and an the Drives window of Ubuntu it tells me the SSD is SDB and the HD is SDA. I would expect the SSD to be SDA ...