I deleted my /dev/null. How can I restore it?

  • 6
    I once found that /dev/null was replaced with a normal file which only root could write to. I thought for a moment that I would have to reinstall everything but as mentioned below, the recovery is trival if you know the trick. Dec 24, 2011 at 12:15
  • 1
    I managed to remove /dev/null by getting my pipe wrong flipping $ and & around when running an rm command in a script. Ouch!
    – flickerfly
    Oct 9, 2015 at 22:28
  • @flickerfly You develop scripts as root? Jan 14, 2020 at 14:02
  • 3
    If the permissions are required, you have to test it eventually. Didn't say it was in production.
    – flickerfly
    Jan 14, 2020 at 15:27

3 Answers 3

mknod /dev/null c 1 3
chmod 666 /dev/null

Use these command to create /dev/null or use null(4) manpage for further help.

  • 5
    For completeness, I'd note that this applies to all linux-based systems; other systems may have different numbers.
    – Random832
    Dec 21, 2011 at 14:53
  • 2
    Also this only sets up the device file itself, it will not restore its permissions. You'll have to chmod go+w it manually.
    – Attila O.
    Jul 3, 2015 at 9:44
  • 7
    The number of the beast!
    – wefwefa3
    Nov 6, 2015 at 16:21
  • 14
    mknod -m 0666 /dev/null c 1 3 - same thing but shorter
    – fnkr
    Oct 23, 2017 at 15:06
  • 1
    mknod -m 0666 /dev/null c 1 3 worked perfectly to restore /dev/null on CentOS 7, just to let other know.
    – Bozzy
    Jan 24, 2019 at 10:13

Under many traditional unices, you can recreate devices with their default permissions with the MAKEDEV script. This script is traditionally in /dev but is in /sbin on Ubuntu. Pass it an argument that indicates what devices you want to create; on Ubuntu that's std (you can write MAKEDEV null as well, that creates null as well as a number of other devices).

Under modern Linux systems running udev, you can tell udev to recreate all or some devices based on available drivers and connected hardware, through udevadm trigger:

udevadm trigger --sysname-match=null
  • Is this answer still current? I'm on CentOS 7 and I've just overwritten my /dev/null by mistake, the udevadm trigger --sysname-match=null trick didn't work for me, while mknod -m 0666 /dev/null c 1 3 worked perfectly.
    – Bozzy
    Jan 24, 2019 at 10:11
  • @Bozzy I know it worked with the pre-systemd udev. I haven't tried recently, but as far as I know this should still work. If you add --verbose, does it list /sys/devices/virtual/mem/null ? Jan 24, 2019 at 22:49
  • Yes, it lists that. I've tried to overwrite again /dev/null on my dev machine, but strangely enough I'm unable to do it here, so I can't do a more in-depth analysis now...
    – Bozzy
    Jan 25, 2019 at 10:18

When I accidentally deleted /dev/null, a simple sudo rebootseemed to restore it. It did cause my desktop icons to go crazy, but no damage seemed to be done If that doesn't the other answers probably will be more help

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