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Linux Admin Quick Notes

guideslinux

Short admin snippets I keep needing just often enough to write down.

Extra drives in fstab

Use UUIDs in /etc/fstab so device names do not randomly ruin your day.

UUID=<UUID> <PATH> ext4 defaults 0 2
UUID=<UUID> <PATH> ext4 defaults 0 2

Get UUIDs with:

lsblk -f

GRUB os-prober

If GRUB is not finding another OS, enable os-prober in /etc/default/grub:

GRUB_DISABLE_OS_PROBER=false

Then regenerate the config:

sudo os-prober
sudo update-grub

Simple DNS fallback

If you find your laptop not connecting to the internet for some reason, then check your DNS. Here are some fallbacks you can use in /etc/resolv.conf:

nameserver 1.1.1.1
nameserver 8.8.8.8

TLP power profiles

sudo tlp power-saver
sudo tlp balanced
sudo tlp performance

Brightness on startup

echo "brightnessctl set 100%" | sudo tee -a /etc/rc.local

Sudo password feedback

sudo visudo
Defaults:<USERNAME> pwfeedback

Remove :<USERNAME> if you want it for all users.

Vial udev rule

Vial needs a udev rule before it can talk to supported keyboards without extra permission drama.

export USER_GID=`id -g`; sudo --preserve-env=USER_GID sh -c 'echo "KERNEL==\"hidraw*\", SUBSYSTEM==\"hidraw\", ATTRS{serial}==\"*vial:f64c2b3c*\", MODE=\"0660\", GROUP=\"$USER_GID\", TAG+=\"uaccess\", TAG+=\"udev-acl\"" > /etc/udev/rules.d/59-vial.rules && udevadm control --reload && udevadm trigger'

Source: Vial Linux udev manual.