cd (change directory)

cd myfolder

Changes the current working directory to “myfolder”

cd ..

Go up one level to the current working directory.

cd ../..

Go up two levels to the current working directory.

cd /

Changes the current working directory to the root directory.

cd ~

Changes the current working directory to your home directory.

mkdir (Make directory)

mkdir Photos

Create a new folder called “Photos” in the current directory.

mkdir /Photos

Create a new folder called “Photos” in the root directory.

mkdir ~/Photos

Create a new folder called “Photos” in your home directory.

ls (list)

ls

list the file names in the current working directory.

ls -l

list the file names with “long” description/information (size, privilages, etc)

ls -a

list “all” file names in the current working directory including the hidden files.

ls -l *.jpg

list the file names ending in “.jpg” and display it in “long” description format(-l)

cp (copy)

cp my.cnf /etc/my.cnf

Copy the file “my.cnf” and put it inside the root -> etc folder.

cp tax05.db ~/Taxes

Copy the file name “tax05.db” and put it inside my home directory -> Taxes folder

cp “.jpg ~/Photos

Copy all the files with “.jpg” extention and put them inside my home directory -> Photos folder

cp -R ~/Docs /backups/’Docs Backup’

Copy the entire “Docs” directory from my home page and put it inside the root -> backups and call it “Docs backup” (use quotes if you use folder names with space. example: ‘Docs Backup’ (-R stands for “Recursive”)

mv (Move or Rename)

mv badletter.txt niceletter.txt

Rename the file “badletter.txt” to “niceletter.txt” in the current directory.

mv Pictures Photos

Rename the folder “Pictures” to “Photos” in the current directory.

mv *.jpg ~/Photos

Move all the files with “.jpg” extention and put them inside my home directory -> Photos folder

rm (Remove)

rm ~/BadPhotos/*.jpg

Delete all the files with the ‘.jpg’ extention inside your home directory -> “BadPhotos” folder.

rm -R Temp

Delete the “Temp” directory and all of its contents in the current directory (-R stands for “Recursive”)

rm -fr Temp

Delete the “Temp” directory and all of its contents including write-protected files without prompting in the current directory (-f stands for “force” -r stands for “recursive”)

find (files and folders)

find ~ -name myletter.doc -print

Search for the file names “myletter.doc” inside my home directory and print the result to the screen

sudo find / -name mysql -print

Search for the file and folder names “mysql*” starting from the root directory and everywhere within it and print the result to the screen. (use “sudo” to get root access temporarily.)

find . -name myletter.doc -print

Search for the file names “myletter.doc” inside the current directory and print the result to the screen

find . -name ‘myletter*’ -print

Search for the file names starting “myletter” inside the current directory and print the result to the screen

locate (similar to find)

locate ~ -name myletter.doc

Search for the file names “myletter.doc” inside my home directory and print the result to the screen

pwd (print working directory)

pwd

Displays the pathname of the current working directory.

who (who logged in)

who

Displays who is logged into the system.

who am i

Displays my user name.

who -uH

Displays who is logged into the system including heading “H” and idle time information.

su (set user) - type exit to switch back to your own identity

su

Temporarily become the root user. (this will give you root access privilages and the most control over the OS) - it will prompt you for the administrator password.

su username

Temporarily become another user called “username” (replace “username” with the user that you wish to use as your new identity - this will give you access privilages for the “username”) - it will prompt you for the that user’s password.

sudo (set user and do . . . . . . ) - similar to su except ’su’ will give you prompt but ’sudo’ you can start typing commands right after the ’sudo’ command.

sudo find / -name mysql -print

Temporarily changes your identity to the root user so you can search for all the files including the once that require root access privilage. It prompts you for administrator/root password

sudo Bobuser rm /Users/Bobuser/Photos/myphoto.jpg

Temporarily changes your identity to the “Bobuser” identity so you can delete a photo named “myphoto.jpg” from the home directory -> Photos folder belonging to Bobuser - It prompts you for “Bobuser”’s password.

ps (running processes)

ps -aux

List detailed information on all running processes.

top (CPU-intensive processes currently running) - press the “q” key to quit the “top” utility

top -us10

List all running processes sorted by CPU usage - descending and updating every 10 seconds - don’t forget to press the “q” key to quit, otherwise it will run continuously.

kill

kill -9 160

Terminate the process ID # 160 at once without any hesitation.