461 Help: Overview

UNIX is a very powerful command-line operating system, and Linux is our particular incarnation of UNIX.

You will use the UNIX command line to launch programs like Csound and Common Music, tell the computer to play back a sound, make directories and copy/move files, switch back and forth between different programs, and more.

Some things that you can do via UNIX you can also do via the KDE desktop, such as moving files around. However, many things for this course can only be achieved through the UNIX commands. You will serve yourself well by becoming comfortable with both Gnome and UNIX.

BASICS

• You execute UNIX commands by opening and terminal window and typing commands into it.

  A very important difference between UNIX and other command-line systems (such as MSDOS) is that UNIX is CASE SENSITIVE. The filename Foo.TXT is not the same as the filename foo.txt.

  The command to execute Csound is a good example of a UNIX command:

  csound -d -A -o mysound.aiff mysound.orc mysound.sco

  • csound is the command
  • -d -A -o are "flags" that set various options for the command. Flags are preceded by a "-".
  • mysound.aiff mysound.orc mysound.sco are the filenames that are going to be operated on.

CHANGING YOUR PASSWORD
• Because we use the Kerberos 5 password system for access to our machines, your local password is the same as your UW net-id password. If you wish to change it, you must do so using the resources provided by the UW.

CHECKING EMAIL

• To check your email, enter the following in Unix:

  ssh dante

  (Or replace "dante" with whatever machine your email account is on.)

REFERENCE LINKS

• The UW's Center for Academic Computing provides the following helpful resources. The CAC information applies to the 'uniform access' computers such as Homer and Dante, so not all things will apply in the Computer Music environment.

  • The main Using UNIX on Uniform Access Computers page.
    • UNIX Quick Reference
    • UNIX for New Users

BASIC UNIX COMMANDS

• COMMAND	ACTION
  GETTING HELP
  man <command-name>	brings up a manual page for <command-name> these can take some getting-used-to, but are very helpful for figuring out how better to use a command
  <command-name> --help	for most UNIX commands, this will bring up a basic help page with information on flags available, etc.
  LOGGING IN
  whoami	to see who is logged in on a specific machine
  NAVIGATION
  cd directory_name	change to specified directory if no directory is specified, you will return to your home directory /Music401/yourname
  CD ..	move up one directory level ../../../ would move you up three directories
  CD	change to your home directory
  CD ~/SND	change to the SND folder inside your home directory (~ is a shortcut for your home)
  pwd	gives pathname of the directory you're in right now ("present working directory")
  WORKING WITH FILES
  more filename	shows contents of a file one screen's worth at a time you cannot edit using more
  cp filename newfilename filename newfilename	copies the first file listed into a file with the second name if a file by the name of newfilename already existed, you will overwrite it
  mv filename place_or_newfilename	moves a file to a file of a new name (a/k/a renames) OR moves a file to a new location (a directory, for example)
  rm filename	removes (forever) a file
  ls	lists all files and directories within your current directory. on our UNIX system, directories will have a slash (/) before their names
  ls -l	list files in "long" format -- giving extra information like permissions, size, etc.
  ls -a	list "all" files, including hidden files (hidden files are files that start with a "." -- often used to store configuration settings for applications
  WORKING WITH DIRECTORIES
  mkdir directory_name	creates a directory
  rmdir directory_name	removes a directory does not work if anything is in the directory

HELPFUL TRICKS IN THE BASH SHELL

• When you are typing commands in a terminal window, this is sometimes also called typing into the shell. The shell is the environment that lets you type commands into UNIX

  There a many different types of shells that can run under UNIX, each providing different, special capabilities. The computers in Computer Music are set to run the bash shell (a.k.a.Bourne Again Shell). It is the standard UNIX C shell with some extra features.

  Here are some of the most useful:

  Command Line Editing

  • Typing the Up-Arrow key makes the previously executed command appear.
    You can keep hitting up-arrow to keep moving back through history.
    The down-arrow key moves forward in history.
    
    
  • You can use the Left-Arrow and Right-Arrow keys to move back and forth in a command line.
    You can then edit the line by deleting and typing characters.
    
    
  • The following Xemacs-like commands also work:
    • Ctrl-a jumps to the beginning of the line.
    • Ctrl-e jumps to the end of the line.

  
  Auto Completion

  • To repeat your previous command, you can just enter !.
    
    
  • To repeat a previously-used command, type ! followed by enough letters of the command to uniquely identify it.
    For example, if I had recently executed a Csound command and now wanted to execute the same command again, I could type:

    cootie 6$ !cs

    and the computer would respond by executing my last csound command:
    
    csound -d -A -o ex1b.aiff ex1b.orc ex1b.sco

  • When you are entering a command that references an existing file, type in a few letters of the filename and then press tab -- UNIX will then attempt to auto-complete the filename based on what you've typed in.