Basic Linux Commands
One does not need to know very many commands in order to get around on a connection to a remote machine pretty easily. Here we give a simple list of some of the most commonly used commands for Linux/Unix. Note that most commands can accept options that change their behavior. For example, ls provides a listing of the contents of the current directory, while ls -l gives that listing in long format, including many more details about each file in the directory. On the other hand, ls -a lists all the files in the directory, including the "hidden" ones. We can mix options simply by chaining them together; e.g. ls -la gives a listing of all files in a long format.
Remember that you can get a full description of the usage of any command by typing man commandname in a terminal.
| Command | Function | Example Formats |
|---|---|---|
| cd | Change Directory |
cd cd directory/path |
| chmod | Change Mode - file permissions |
chmod u+w file_name chmod 755 file_name |
| cp | Copy files | cp from_file to_file |
| exit | Exit the shell | exit |
| less | List contents of a file | less file_name |
| ls | List filenames in a directory | ls ls -l ls file_name |
| man | Manual pages |
man cp man mv |
| mkdir | Make a Directory | mkdir directory_name |
| mv | Move a file | mv from_file to_file |
| nano | Start a primitive editor | nano file_name |
| pwd | Print Working Directory | pwd |
| rm | Remove a file | rm file_name |
| rmdir | Remove a Directory | rmdir directory_name |
There are a few "wildcard" characters that can match many things. The question mark matches any single character. Thus, ls image?.jpg would list all of the files image1.jpg, image9.jpg, and imageA.jpg on a directory, but would not list image23.jpg The asterisk matches any number of characters, so that ls image*.jpg would list image1.jpg, image23.jpg and image49027.jpg.
