Linux commands

Linux general commands

Command	Description
alias	Creates a commnad
alien	Migrate packages from .rpm to .deb and vice versa
apropos <subject>	Sows commnads related to a subject
apt-get	Package installation and system update
cal	Shows calendar
cat <filename>	Shows file content
clear	Clear screen
date	Shows date
dd
df	Shows the disk ussage. Example: df -h
dpkg	.deb package installation: sudo dpkg -i packagename.deb
du	Disk ussage
export VARIABLE=VALUE	To create system variables
fsck	Check file system
fdisk	Disk partition utility
find	Find files
free	Shows free memory
grep <text>	finds text
head	Shows file start (-n, -f,...)
history	Shows the commnad history (contained in ~.bash_history)
info <command>	Sows command info
ln	Create simbolic links
lsblk
lspci -v	View PCI device information
lscpu	List cpu cores
lsof	sudo lsof -i -n | egrep '\<ssh\>'
man <command>	Sowhs a command manual page
mc	Midnight commander. File system navigation
mkdosfs -F32 /dev/mmcblk0	Format SD card with FAT32
more <filename>	Shows file content, screen by screen
mount	File sistem mounting
pwd	Shows working directory
rsync -a ruta1 ruta2 [--exclude=/{dir1, dir2..]/]	Copies files from ruta1 to ruta2 excluding dir1, dir2,...
scp	Copy files to a remote machine over ssh protocol
ssh	ssh (Secure Shell)
sed	String replacement
sort	Sorts the content of a file line by line
su	Log as root at the terminal (sudo su)
sudo <command>	Execute command as root
tar	Compress/decompress tar files
tail	Shows file end (-n, -f, ...)
touch <file_name>	Creates an empty file
tty	Shows the terminal where you are connected
uname	Shows system info
visudo	visudo is used to securely edit /etc/sudoers
wc -l	Counts lines
wget	Download files/web pages
vim	Text file editor
who	Connected persons
whoami	Who am i
<cmd1> | <cmd2>	Pipe: takes the output of command1 as input of command2. example: cat /etc/passwd | sort | more

Users and File permissions

Command	Description
adduser	Add users	w	Show connected users
chown <NewOwner>:<NewGroup> <File>	Change file owner
chgrp <NewGroup> <File>	Change group of file
chmod	Change file permissions

Processes

Command	Description
CTRL + C	Stop process
CTRL + Z	Pause process
%PID	Recover paused process
<command>&	Execute command in second plane
bg <command>	Execute command in second plane
ps	List processes
pstree	Show process tree
top	Processes viewer
htop	Process viewer more advanced than top
kill %PID	Terminate process
nice, renice	Process priorities: nice -n <command>
nohup <command>	Execute process avoiding its stop if the terminal is stopt
pgrep <pattern>	Retruns process that matches pattern
locate <program>	Returns program path

Firewall

Command	Description
iptables	Firewall rules
service iptables [start, stop]	Activate/deactivate firewall
route -n	Shows routing table

Networking

Command	Description
netstat
nmap	Network mapping
nm-tool	Network monitor tool
nm-connection-editor	Network monitor editor
ifconfig	Show network configuration
iwconfig	Show WiFi connections
service networkmanager restart	Restart network daemon

Network Manager configuration files:

• /etc/NetworkManager/system-connections/name-of-connection

Network configuration file:

• /etc/network/interfaces

Linux key files/directories

See: Linux key files/directories

Programs

Command	Description
git	Software repository
coursera-dl
jp2a	Jpg to ASCII
john	John the ripper
macchanger	Change MAC address
openvpn	Connect to VPN
terminator	Advanced terminal
virtualenv	Create virtual enviroments
youtube-dl	YouTube video downloader

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