CSE 303 Homework 1

Due: Friday 1/11/08
Turnin: nothing to turn in

This assignment is designed to begin your experience using a Unix shell (in particular, bash, although most commands used here will work in any shell, as they have a lot in common). Do this assignment, but don't hand anything in about it. You can do this on any Unix machine, or with cygwin (unless you've failed to install something needed by one of the commands). We have tested that everything works as expected on attu.

Listed below are a set of commands to execute. There are explanations for what some of them do, but not for all. When you execute them, what they do may be apparent to you. To find out more, though, you can always use man. For example, man pushd will tell you about the pushd command.

If you see the following notation: Ctrl+X;  on a line, hold down the control key and press the letter specified. (Ctrl+X, for example, specifies the cut operation in Windows.) Don't hold down the shift key to make the letter uppercase.

echo Print this
1. echo $SHELL

If your shell is not bash (it will probably be csh in that case), it would be better to change your shell. Unfortunately, we can't give you instructions on how to permanently change your login shell to bash, because it depends on more things than we can predict. The commands below work (for us) on attu.cs.washington.edu. Especially if you have trouble with this step, this page may provide useful additional information.

1. cat /etc/shells
   Prints full path names for all legal login shells on this system.
2. chsh -s /xxx/bash
   The argument to chsh should be the full path name for bash, as printed in response to the previous command (e.g., /bin/bash on attu.cs.washington.edu).
   Note 1: This affects what shell is created in the future when you login, not the one you're working in now.
   Note 2: This update must propagate to a number of servers, and can take up to a few hours to become effective every time you login.
   Note 3: This step can not work. See this page.
3. /xxx/bash
   Your keyboard is now connected to a bash shell.
 
2. ps

   A list of processes with the same user id (uid) as the shell will be printed. Since the uid of the shell is your user id, these are the processes you are running when this command executes. You should see two of them, your shell and the ps command itself.

3. cat /usr/include/stdio.h
   Prints that file. The file contents won't make much sense to you. Sorry, but I need a reasonably large file that exists on pretty much all Unix systems for this example.
4. less /usr/include/stdio.h
   less is a program that scrolls the printing of long files. It lets you move forward, move backward, search, and many other things. Try typing the following while it's running:
   • [space]
   • u
   • [space space]
   • p
   • /fileno
   • n
   • n
   • q
5. man man
   No need to read this page in detail at this point, but man is the Unix word for 'help.' The format of the page you see is followed by all other man pages: how to invoke it is at the top, a brief description of what it does follows, followed by often a large amount of information with more details.

   man displays the output using less, so the commands you just learned about less work.

6. man -k userid

7. pwd
8. ls /var
9. cd /var
10. pwd
11. ls
12. ls -l
13. ls -a
14. ls -al

15. lw[backspace]s
16. loops[left-arrow, then backspace three times, then the enter key]
17. erase this line[Ctrl+u]

18. cd
19. pwd
20. mkdir HW1
21. cd hw1
22. cd HW1
23. pwd

24. ls -al
25. ls -al .
26. ls -al ..
27. cp /usr/include/stdio.h testfile
28. ls -l

29. mv testfile test
30. ls -l test
31. ls -l te[now hit a tab]
32. cp test test2
33. ls -l te[now hit 3 tabs]
34. rm test2
35. ls
36. cp test test2; ls
37. cp test notTest; ls -l
38. ls -l *
39. ls -l t*
40. ls -l test*
41. ls -l *2*

42. cd ..
43. pwd
44. mkdir HW1prime
45. cd HW1prime
46. ls ../HW1
47. cd /etc
48. pwd
49. ls ~
50. ls ~/HW1
51. cd

52. pushd /etc
53. pwd
54. pushd /var
55. pwd
56. popd
57. pwd
58. popd
59. pwd

60. pu[now hit tab twice, then type an 's', then hit tab again] /etc
61. popd

62. history
63. [up arrow 2 times]
64. !!
65. !h
66. !pu
67. !pop

68. ls /usr/include/stdio.h
69. ls !$
70. [up arrow, then the left arrow, then type to create a ls -l version of the last command]
71. [up arrow twice, then the Ctrl+a Ctrl+f Ctrl+f Ctrl+f, then type to create a ls -l version of the last command]
72. ^stdio^paths

73. alias list='ls -al'
74. list
75. cd
76. list

77. ls -l
78. ls -l >test.out
79. less test.out
80. ls -l >>test.out [Note the two right angle brackets]
81. rm test.out

82. rmdir HW1prime
83. list
84. rmdir HW1
85. rm -r HW1
86. list

87. info bash

    info is an alternative to man. It often provides more and better organized information. It is based on a notion something like web links. The links are the asterisk'ed lines (or maybe just the asterisk and the following word, or ... info info should reveal the exact rules). You follow a link by getting the cursor on it (using the arrow keys) and then hitting the enter key. You go 'back' by typing u (for up).

    Do the following:

    • Put the cursor on the asterisk next to 'Introduction'.
    • Hit enter.
    • u
    • q

How to terminate the shell can vary a bit, depending on what system you're on. In some cases (basically, where that shell is your only connection to the machine you're talking to - a simple ssh to a remote server, say), terminating the shell is also how you logout. Here are some possible alternatives (all intended to logout):

• Ctrl+d
• logout
• exit