This Is Your Brain On Informatics: Linux Commands

General Linux Command Info

• Almost every single command should have an argument (an input for a function)
• A filename in Linux refers to both a file's name and a directory's name

Common Linux Commands

Command	Syntax	Description
cat	cat filename	Display file’s contents to the standard output device (usually your monitor)
cd	cd /pathname	Change to the given directory
chmod*	chmod options mode filename	Changes a file's permissions.
chown	chown private_owner:group_owner filename	Changes ownership of the file
clear	clear	Clears the screen by scrolling (does not delete anything)
cp	cp options source destination	Copies a file from the source to the destination
find	find /pathname string	Starts at the indicated directory and searches for the string in a filename
grep	grep options pattern filename	Searches for the pattern in the file
ifconfig	ifconfig	Displays the current networks available and various information about them
ll	ll /pathname	List Long: lists the details of the entire directory or file indicated
ln	ln options source destination	Link: creates a shortcut. Use -s for the options to create a soft link (more capabilities)
ls	ls /pathname	Lists the files and directories in a given directory
man	man command	Opens the manual page for the given command
mkdir	mkdir options filename	Makes a directory at the given location with the given name
mv	mv options source destination	Moves a file or directory from the source to the destination
pico	pico filename	Opens the given file in the pico text editor
pwd	pwd	Displays the pathname for the current directory
rm	rm options filename	Removes the given file. If -rf is used for the options, a directory and its roots will be removed as well
ssh	ssh options user@machine	Remotely logs into the given machine with the given user name
sudo	sudo command	Allows super user privileges for the given command (requires root password). sudo su allows login to root
tar	tar -xzvf filename	Extracts files with the extension *.tar.gz or *.tgz
touch	touch filename	Creates an empty file with given name
wget	wget internet address	Downloads a file from a given internet address

*Notes on chmod

chmod has several input options. Using a + and an r, w, and/or x will add read, write, or execute permissions respectively to the given file. A - will take these away. The other system is a binary system in which there are permissions for the private user, the group, and the public given as 000 000 000 where each set of three 0's equals the private user, group, or public respectively. The first 0 in each group is for reading permission, the second for writing, and the third for executing. Because it is binary 100 000 000 (permission for the private user to read only) will be written as 400 in the command line (after translating the binary to decimal where 100 = 4)