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	returns the full path of matching files, either in full file system (with quotes) or limited to home folder (without quotes)	find -name “*my_file.*” find -name *my_file.*
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 .
top	prints various system capacity usage statistics for each running process, and updates every 3s interpret output	top

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;