Useful Linux Commands

• To see what's in the directory that you're in, type ls
• To navigate "up" into any higher directory, type cd ../
• To navigate "down" into a directory named foo, type cd ./foo
• To create a file named 'foo', type touch foo
• To create a directory named 'foo', type mkdir foo
• To remove a file named 'foo', type rm foo
• To remove a directory named 'foo', type rmdir foo
• Print working directory, use pwd
• To move a file to a directory, type mv filename directory_path
• Just about any program, when you type it's name and -h or --help will print out a usage message.
• if you want to view what's in "foo": less foo or cat foo.
• To open a file or URL in the user's preferred application, use xdg-open { file | URL }. Basically works like a double-click!!
• To find a file or directory named "foo", type: locate foo (for case insensitivity use locate -i foo) or whereis foo
• If you don't know about "foo", type: info foo or man foo
• To find files in a directory, use find {directory} -name {name}. Use -type f for files and -type d for directories
• To search inside a file named 'foo', use grep "text to be searched" foo
• To kill a process, use kill -15 {pid} or kill -9 {pid} where 'pid' is the process id.
• Use !! to repeat the last command entered. e.g. sudo !! is same as sudo {previous command}
• To save the output of a command 'cmd' in terminal in a file named 'foo', use cmd > foo
• To know your username :), type whoami

If you know any other interesting command or some linux tricks, please create a pull request!