| Command | Action | 
| ls | list the files and subdirectories for the current directory | 
| ls -l | list the files and subdirectories for the current directory (long format) | 
| cd X | change directory to directory named X | 
| cd .. | go up one directory level | 
| pwd | Present Working Directory -- identify the name of the current directory | 
| date | display date and time | 
| man X | display manual pages for command X | 
| more X | display contents of file named X | 
| mv X Y | move a file; i.e., rename the file X (old) to the name Y (new) | 
| cp X Y | copy the file named X as the new file named Y | 
| rm X | remove a file; delete file named X | 
| rmdir X | remove a directory; delete directory named X | 
| mkdir X | make a directory; create directory named X | 
| pico X | invoke `pico' text editor for file named X | 
Useful information regarding UNIX can be found at innumerable web sites. Some useful sources are