Linux

name of command

description of command’s functions

useful specific usages of command with arguments

commands as inputted to cli

cat

concatenates files contents to the terminal

concatenate with line numbers

cat -n joyce.txt

du

shows the size of all files in the current directory

`du -sh *

find

find files in current directory modified in last 24 hours

find . -maxdepth 1 -mtime -1

find file named main.py in directory with specific name

find ./Sync -name main.py

find file with .py extension

`find ./Sync -name ‘*.py’

grep

used to search text and strings in a given file

find string within current folder, n shows relative line number and r recursively searches subdirectories, . is current directory

grep -nr 'tab-desk' .

search any line that contains word in filename

grep ‘word’ filename.txt

perform case-insensitive search for word in file

grep -i ‘word’ filename.txt

look in all files in current directory and in all subdirectories for word

grep -R ‘thank’

search and display number of times string appears in file

grep -c ‘thank’ file.txt

find and display all lines that contain a word

grep -F ‘thank’ file.txt

find and display all lines that contain a word as a whole word(will not display thanks)

grep -F -w ‘thank’ file.txt

less

view full file in terminal with scrolling and search controls, vim controls (j, k, q, / to search)

permissions

-rwxrwxrwx first character is - for file, d for directory, l is for symlink. r is read, w is write, and x is execute, first set is for user, second set is for group and third set is for others outside user and group. - means permission revoked

add john to debian-transmission group

sudo usermod -a -G debian-transmission john

change the folder ownership

sudo chgrp debian-transmission /mnt/imp/Media/Movies/Idiocracy_2006

grant write access to the group

sudo chmod 770 /mnt/imp/Media/Movies/Idiocracy_2006

grant access for plex to access files

chmod 755 /plexmedialibrary

add existing user to a secondary group

usermod -a -G GROUP USER

rsync

copies file to new directory and shows progress

rsync —progress file.txt ~/john/

copies file to new directory, renames file and shows progress

rsync —progress file.txt ~/john/target.txt

scp

copies file from from mbrain to current directory away from house

scp -P 570 97.120.181.83:/mnt/backup/sambashare/originals/IMG_1868.jpg ./

sed

stream editor that works on piped input or files of text. Instructions are provided and it works through the text. Select txt, substitute text, add lines to text, delete lines from text, modify (or preserve) an original file.

echo text to sed through pipe and substitute portion of the text

echo howtogonk | sed 's/on/ee/'

select and display lines 1-4 of a file

sed -n '1,4p' joyce.txt

select multiple line selections in a file and display

sed -n -e '1,4p' -e '24,27p' joyce.txt

substitute text in a file, g for globally as to not stop at the first occurence of a line, i for case insensitive (tobechanged or Tobechanged), and p to print the output to the terminal

sed -n 's/tobechanged/substitute/gip' joyce.txt

substitute text in a file using multiple letters as the selector

sed -n 's/[Dd]ay/week/gp' joyce.txt

insert text after a line that begins with a specified string

sed '/JIM/a --> Inserted!' joyce.txt

sshfs

mount dooky to ~/mnt on WSL

sshfs -p 570 192.168.0.16:/mnt/dooky /home/john/mnt umount /home/john/mnt

mount ~/ on Humbert to ~/Humbert on WSL

sshfs -p 571 192.168.0.11:/home/john /home/john/Humbert

service

reload vs restart

restart shuts the program down and restarts, rewriting settings to original state

reload instructs the program to reload its configuration

sudo service transmission-daemon restart sudo service transmission-daemon reload

start a service

sudo service transmission-daemon start

stop a service

sudo service transmission-daemon stop

status

sudo service transmission-daemon status

ufw

unblock port 9260

sudo ufw allow 9260

status

sudo ufw status sudo ufw status numbered