Linux Commands – top ten or thereabouts

Commands I’m forever Googling…

Command	Does what?	Example
history	Prints previously executed commands	history
!! !n !-n	Re-executes a previous command: !! – last command (inc sudo !!) !n – command at history line n !-n – n commands ago	!! sudo !! !702 !-1
pwd	Print Working Directory	pwd
rmdir	Remove empty Directory	rmdir
rm	Remove any Director	rm
locate	find file	locate -l hello*
df	disk space	df -m
du	disk usage	du Documents
ls -lah ls -alSr	LiSt directory with file sizes in size order (S), in reverse (r)	ls -lah ls -alSr
ps	Process Status	ps aux (note “aux” are a, u & x options)
service	list enabled services detail specific service	service –status-all service <service-name> status
cal	show this month show any month	cal cal 10 1971
diff
find
grep
&	run in background
md5sum
netstat
free		free -h -s 3 free -m
mysqldump
tail /path/to/file	prints the last 10 lines of the file	tail ./Documents/my_file.txt sudo tail -f /var/log/syslog
tail -f /path/to/file	prints the last 10 lines and keeps live updating the output as its added to – useful for live viewing an updating/live log
sudo systemd-resolve –flush-caches	flush client dns cache (not on Raspbian)
scp	Secure CoPy In this –> example scp copies a file named “file.name” from “host” to the same filename (“.”) on the local machine	scp user@host:file.name .

And package management…

apt	apt-get / -cache	Does what?
apt install	apt-get install	Installs package
apt remove	apt-get remove	Removes package
apt purge	apt-get purge	Removes with config
apt update	apt-get update	Refreshes repository
apt upgrade	apt-get upgrade	Upgrades all upgradeables
apt autoremove	apt-get autoremove	Removes unwanteds
apt full-upgrade	apt-get dist-upgrade	Upgrades, handles dependencies
apt search	apt-cache search	Searches for packages
apt show	apt-cache show	Package details

Nano…

Esc + $	Enables soft line wrapping	Esc + $ is achieved by pressing and releasing <Esc> then holding <Shift> and typing <4> (Shift+4 = $)

A few Node-RED goodies…

sudo systemctl start node-red	Restart Node-RED
cd .node-red sudo nano settings.js	Edit settings
sudo crontab -e	Edit crontab

A few MacOS ones too…

open .	Open current folder in Finder from Terminal

MySQL…

To list the size of each database:

select table_schema, sum((data_length+index_length)/1024/1024) AS MB from information_schema.tables group by 1;