Lab1 Unix

Preparation

• Getting Started on Unix
• Unix Command Summary
• A brief introduction to Unix file redirection and pipes

A few more things you need to know

• Many unix commands expect one or more filenames as input (e.g. grep word file, looks for word in file). Whenever a list of files is expected you can instead you "wildcards" to specify a group of files. The simplest wildcard is "*" which can stand for anything. E.g. more *.java will list the contents of all files ending with .java in the current directory. You can even use just "*" which will match all files in the current directory.
• To move down into a subdirectory type cd subdirName. To move up to the parent directory type cd .. (that's cd followed by a space followed by two dots with no intervening space).

What to do

1. Log on to one of the lab machines. Enter your username. Then select Options/Session/CDE (Common Desktop Environment). Enter your password. There seem to be some problems with the default desktop if you do not select CDE. On your own time you are encouraged to explore both and see which you like best.
2. If you aren't already very familiar with the "bash" shell, I strongly encourage you to switch from the default "csh" shell to "bash". You do this by
   1. Log into unix.ic.ucsc.edu by typing "ssh username@unix.ic.ucsc.edu" (where username is your username), then enter your password when prompted. These are the same ones you used to login to the lab machine.
   2. Once logged into unix.ic.ucsc.edu, you should see the current time and the prompt character ">". Type "chsh".
   3. When it prompts you for your new shell type: /usr/bin/bash.
   4. Type "logout" to leave unix.ic and go back to working on the lab machine.

   The result will not take effect in Consoles or Terminals that are already open, and it may take a few hours before new Consoles or Terminals are created with your new setting. In these cases, you can always invoke bash directly, just type "bash". In any case, when you come to lab next time, you should find that the arrow keys allow you to navigate the command history and edit the current command (we'll explore these features in a minute).

   To see what shell you are running, log into a new machine open a new Terminal or Console and type ps. This will show you a list of processes running under your username. If you see csh listed (as opposed to bash or tcsh), the new shell has not yet taken effect.

   Note: Some of you may already have some experience with UNIX and prefer a different shell environemnt (tcsh, for example). If you want to use that instead of bash, that's fine, but please keep in mind that when answering questions and providing examples, we will be assuming you are using bash.

3. The bash shell does everything csh does but also has some additional features. Most importantly (in my view), are filename completion and command editing.
4. After typing several commands using bash, try using the arrow keys to see what happens. You can edit previous commands and then execute the modified command. You do not need to move the cursor to the end of an edited command, just hit the return key when ready.
5. Type cd /afs/cats/courses/cmps012a-cm/b but DO NOT hit the return key, instead hit the tab key. Notice how bash is able to complete the filename for you (there is only one way to finish).
6. Now hit the return key to actually cd into that directory. Type cd c and the tab key. Notice that this time your computer will beep after partially completing the filename. There are multiple ways to continue. You can push tab again to see a list of completions or type some more characters if you know what you want next.
7. Filename completion and command editing can save a lot of time and typing.
8. Get back to your home directory by typing "cd" (then hit return/enter which you always need to finish a command).
9. Make a class directory called "12a" (use mkdir).
10. Change to the new directory.
11. Make two subdirectories, "lab" and "programs".
12. Change to the new programs directory.
13. Make a subdirectory for each of the 5 programming assignments. Call them prog1, prog2, ...
14. Change back to your home directory (just type "cd").
15. Type "ls -R > lab1mkdir.txt" which will put a listing of your directories into "lab1mkdir.txt". (You may get some error message about OldFiles which you can ignore.) You can see what is in the file by typing "more lab1mkdir.txt". The ">" in the command means, instead of sending the output to the console so you can read it, "redirect" the output into the file that comes next - in this case "lab1mkdir.txt".
16. Use grep to find out which file(s) in /afs/cats/courses/cmps012a-cm/book-examples/chap2 contain the word "height". You might want to use cd to first get into the chap2 directory.
17. Use grep and wc to find out how many lines in that same directory (.../chap2) contain the string "int".
18. Try logging into unix.ic.ucsc.edu using ssh.
19. Working with the person next to you, try transfering some test file from their directory to yours using sftp.
    1. Create a file to transfer. One simple way to do this is type:
       1. cat > testfile
       2. something here.. type as much or as little as you want over several lines
       3. When done, type control-d on a line by itself. That is hold down the control key and type the d key.
    2. Type "sftp username@unix.ic.ucsc.edu" to connect.
    3. Once connected you can use "ls", and "cd" just like at a normal Unix prompt, to see and move around in the directories on the remote machine (unix.ic).
    4. Once you are in the directory where the file you want resides, type "get filename" to download the file from the remote computer to the one your are working at (the lab computer or your home computer). The file will be put in whatever directory you were in when you started sftp.
    5. You can also use "put filename" to upload a file from your computer to the remote computer (unix.ic).
    6. When you are done type "quit".
    7. You can read about downloading an sftp program for your home computer at http://www2.ucsc.edu/cats/sc/software/ssh/
20. Answer the post-lab questions in WebCT for the first lab. IMPORTANT: Be sure and submit the post-lab questions BEFORE the end of lab. Even if you aren't finished, submit what you have. If you need extra time, you will have until after 11pm, but you can only get credit if you have attended lab and attempted a solution before the end of lab. This will be the same all quarter.
21. Submit, using WebCT, the "lab1mkdir.txt" file that you created.