Linux commands

Linux general commands

Command	Description
tty	Shows the terminal where you are connected
free	Shows free memory
date	Shows date
cal	Shows calendar
clear	Clear screen
who	Connected persons
whoami	Who am i
uname	Shows system info
du	Disk ussage
df	Shows the disk ussage. Example: df -h
man <command>	Sowhs a command manual page
apropos <subject>	Sows commnads related to a subject
info <command>	Sows command info
history	Shows the commnad history (contained in ~.bash_history)
pwd	Shows working directory
touch <file_name>	Creates an empty file
alias	Creates a commnad
cat <filename>	Shows file content
more <filename>	Shows file content, screen by screen
head	Shows file start (-n, -f,...)
tail	Shows file end (-n, -f, ...)
sort	Sorts the content of a file line by line
<cmd1> | <cmd2>	Pipe: takes the output of command1 as input of command2. example: cat /etc/passwd | sort | more
rsync -a ruta1 ruta2 [--exclude=/{dir1, dir2..]/]	Copies files from ruta1 to ruta2 excluding dir1, dir2,...
grep <text>	finds text
wc -l	Counts lines
find	Find files
apt-get	Package installation and system update
dpkg	.deb package installation: sudo dpkg -i packagename.deb
su	Log as root at the terminal (sudo su)
mount	File sistem mounting
vim	Text file editor
mc	Midnight commander. File system navigation
alien	Migrate packages from .rpm to .deb and vice versa
scp	Copy files to a remote machine over ssh protocol
wget	Download files/web pages
fdisk	Disk partition utility
terminator	Advanced terminal
lspci -v	View PCI device information

• Bulleted list item

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

vnc:escritorio remoto

Firewall

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

Networking

Command	Description
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
john	John the ripper
youtube-dl	YouTube video downloader