Linux - General

Cockpit

dnf install cockpit
systemctl enable --now cockpit.socket
systemctl start --now cockpit.socket
firewall-cmd  --permanent --add-service=cockpit

Gnome

gsettings set org.gnome.desktop.wm.preferences button-layout ":minimize,maximize,close"

Grub

In /etc/default/grub, add to GRUB_CMDLINE_LINUX (GRUB_CMDLINE_XEN):

• dom0_mem=max:1024M dom0_max_vcpus=1

grub2-mkconfig -o /boot/grub2/grub.cfg

systemd

Service Control

Basic use:

systemctl start something
systemctl stop something
systemctl enable something
systemctl disable something

Service definition files in:

• /usr/lib/systemd/system

Deinitions with "@" names have argument passed as parameter, such as:

systemctl status clamd@scan

Show all defintions:

systemctl list-unit-files --type=service

SELinux

getenforce
setenforce 1
setenforce Enforcing
sestatus

Boolean flags:

getsebool -a
setsebool -P httpd_read_user_content

Swap

Add filesystem swap:

fallocate -l 1G /somepath/swap
chmod 600 /somepath/swap
mkswap /somepath/swap
swapon /somepath/swap

Check:

swapon
NAME              TYPE       SIZE   USED PRIO
/dev/sda2         partition    8G 219.8M   -2
/somepath/swap    file      1024M     0B   -3

And then add a line to /etc/fstab to ensure it is enabled at boot:

/somepath/swap                         swap                    swap    defaults         0 0

Timezone

Show available zones:

timedatectl list-timezones

Set and check:

timedatectl set-timezone timedatectl
timedatectl

UDEV

Rules files in /etc/udev/rules.d

Display device attributes with:

udevadm info --query=env --name=/dev/sdg

See also: Udev Rules