A Few UNIX Commands

Getting documentation

• Type man ls to read the documentation describing ls, man man to read about man, etc.
• For a list of many of the available commands, you can list the directories where they are stored: ls /bin, ls /usr/bin, and ls /usr/local/bin, for example. If you're obsessive, you could spend a lot of time with these lists and man.

Directories

• cd destination: Change directories. Move from the current directory (folder) to destination.
  • cd ..: Move to the parent of your current directory.
  • cd: Move to your home directory.
  • cd .: Move to the current directory. (Aren't you glad I shared this one with you?)
• mkdir: make a new directory.
• rmdir: remove an existing directory.

Files

• ls: List the contents of the current directory.
  ls -l: Give a long-form listing, with lots of information about each file and directory.
  • ls -a: Do a normal ls, but include all files whose names begin with a period.
  • ls -F: Do a normal ls, but mark all executable files with a *, and all directories with a /.
  • ls -laF: Do all of the above.
• mv oldFile newFile: Move (or, more precisely, rename) the file oldFile to the file newFile.
• mv file directory: Move a file into a directory.
• cp oldFile newFile: Copy the file oldFile to the file newFile.
• cp file directory: Copy a file into a directory.
• rm file: Remove (that is, delete) a file. There's no "undelete" command, so be careful.
• cat file: "Concatenate" the file--that is, print its entire contents to the screen, all at once. For big files, you'll want to use more file.
• more file: Print the file on the screen, one window's worth at a time. While you're using more, the spacebar will move you forward one screen, b will move you back one screen, the return key will move you forward one line, "/something" will move you to the next line that contains "something," and q will quit.

Command shell goodies

• !!: Execute the previous command again.
• !something: Execute the most recent command that began with "something."
• <ESC>: If you have typed enough of a file name to uniquely identify the file, pressing the escape key will complete the file name for you.
• *: The * represents any string of characters. Thus, ls b* will list all files whose names start with b (UNIX is case-sensitive with respect to file names, by the way, so ls b* will not list files whose names start with B). Similarly, ls *b* will list all files whose names contain a b.