linux_commands_cheatsheet.md

Most usual commands in Linux Cheatsheet!

Command	Arguments	Description
cd		Change the directory
pwd		Output of the current working path
ls		List a folder content
ls	-l	Long Listing
ls	-a	Displays everything even hidden files
cat		Shows the contents of a file or merges files
less		Displays the contents of a file page by page (With additional functions like the search)
more		Displays the contents of a file page by page
stat		Display file or file system status
hostnamectl		Can be used to query and change the system's computer name and associated settings
date		Displays the date and time
cal		Displays the calendar
lsusb		Displays the USB devices
lscpu		Displays information about the CPU architecture
lspci		Detailed information about the PCI devices and buses in the system
lsblk		Lists information about all available or the specified block devices
df		Report file system disk space usage
df	-hT	Disk space allocation with (-h) "human readable" numbers and (-T) file system
uptime		Incl. CPU utilization 1min, 5min and 15min
uptime	-p	-p stands for "pretty"
uname		Displays the OS
uname	-a	-a for all info
touch		Update the access and modification times of each file to the current time. If the file does not exist, one will be created
rm		Remove files or directories
rm	-i *	* means delete all files, with -i prompt before every removal
rm	-f	-f is for force, execute the command either way
rm	-r	Remove directories and their contents recursively
rm	-v	-v is for verbose, explain what is being done
mkdir		Create the Directory(ies), if they do not already exist
rmdir		Remove empty (must be empty) directories => if not use rm -rf
cp		Copy files and directories
cp	-R	-r copy directories recursively
mv		Move (or rename) files
ln		Create symbolic and hard links
ln	-s	Make symbolic links instead of hard links
echo		Display a line of text
paste		Merge lines of files
join		Join lines of two files on a common field
expand		Convert tabs to spaces
unexpand		Convert spaces to tabs
sed		Stream editor for filtering and transforming text (Syntax example: sed 's/this/through-this/g' file.txt)
		s stands for substitute, g stands for global=all
wc		Print newline, word, and byte counts for each file
wc	-l	-l Print the newline counts (-l is an l stands for lines)
chmod		Change file mode bits
chmod	ugo+x␣filename	Set the execute bit for user, group and other for a file
chmod	755␣filename	rwx the user, r-x for the group and r-x for others on a file
chgrp		Change group ownership
useradd		Create a new user or update default new user information (mostly used with RedHat based distros)
useradd	-ms (for example)	-m Create the user's home directory if it does not exist. -s The name of the user's login shell.
adduser		Create a new user or update default new user information (mostly used with Debian based distros)
usermod		Modify a user account
usermod	-aG	-a Add/Append the user to the supplementary group(s). -G A list of supplementary groups which the user is also a member of.
userdel		Delete a user account and related files
userdel	-f	-f This option forces the removal of the user account, even if the user is still logged in. It also forces userdel to remove the user's home directory and mail spool, even if another user uses the same home directory or if the mail spool is not owned by the specified user
groupadd		Create a new group
groupmod		Modify a group definition on the system
groupdel		Delete a group
grep		Search a file for a pattern
grep	-i␣pattern␣file	-i Perform pattern matching in searches without regard to case
tail		Print the last 10 lines of each File to standard output
head		Print the first 10 lines of each File to standard output
cut		Print selected parts of lines from each File to standard output
sort		Write sorted concatenation of all Files(s) to standard output
du		Summarize disk usage of the set of files, recursively for directories
du	-sch	-s display only a total for each argument, -c produce a grand total, -h print sizes in human readable format (e.g., 1K 234M 2G)