Commandline options kernel was started with
cat /proc/cmdline
Distribution version details
lsb_release -a
Kernel details
uname -a
Machine serial number
sudo dmidecode -s system-serial-number
Machine bios version
sudo dmidecode -s bios-version
System log (add -no-tail when piping to something)
journalctl --system -S "2024-03-22 14:00"
Get display details
edid-decode /sys/class/drm/card0-eDP-1/edid
Memory (RAM) details
sudo lshw -C memory
NVMe SSD details
sudo smartctl -a /dev/nvme0
Block device e.g. disk details
lsblk
CPU details
lscpu
USB bus details
lsusb
Firehose of hardware info
sudo hwinfo
Disk space stats in human friendly format
df -H
Service status
sudo systemctl status <service name>
Enable, start and stop to control services
sudo systemctl enable <service name>
sudo systemctl start <service name>
sudo systemctl stop <service name>
System sleep. Look in this file for details.
cat /sys/power/state
cat /sys/power/mem_sleep
cat /sys/power/disk
Mask (disable) particular sleep states.
Use unmask to reenable.
sudo systemctl mask \
hibernate.target hybrid-sleep.target
Examine masked states
sudo systemctl status \
sleep.target suspend.target hibernate.target hybrid-sleep.target
List all available printers
lpstat -pa
List current printer jobs
lpstat
Output will be of the form
Brother_HL_L2300-181 kg 165888 Sun 21 Sep 2025 07:48:03 PM EDT
Here the -181 is the job number.
Remove a print job
lprm <job number>
List jobs that are not completed
lpstat -W not-completed
Restart print service (sometimes needed to reconnect to a printer)
sudo systemctl restart cups
Current window manager
echo $XDG_CURRENT_DESKTOP
Edit GRUB configuration
sudo vi /etc/default/grub
Write out GRUB configuration (Ubuntu)
sudo update-grub
If update-grub is not available
sudo grub2-mkconfig -o /boot/grub/grub.cfg
Find devices via mDNS
avahi-browse -a
Find mDNS name for given address
avahi-resolve-address 192.168.8.1
getent hosts 192.168.8.1
Show details (including size) of a package
apt show <package name>
Networking interface configuration
ifconfig
Trace route to host
mtr 8.8.8.8
List directory contents recursively
ls -R
Redirect stdout of cmd to std.out and stderr to `std.err
cmd > std.out 2> std.err
Redirect stdout and stderr to `out.txt
cmd 2> out.txt
Size of directory
du -sh <directory>
Used and free sizes of all mount points
df -H
Find and print all empty directories
find . -type d -empty -print
Delete all empty directories
find . -type d -empty -delete`
Find and print all files with given extension
find Takeout -name "*.json" -type f -print