CSCI 157: UNIX Power Utilities and Shell Programming

Laboratory Assignment 3

ASSIGNMENT DUE: see calendar on the web

1. TURN-IN a hard copy of the following:

On all homework please include

Your Name
Course Number
Date
ecst login name

Self-test questions page 66. Numbers 3.3 (type cal 1752), 3.6, 3.8, 3.10

Exercises page 66. Numbers 3.7, 3.10

Also answer the following questions on Permissions

1) Give the chmod command to change permissions on file1 to give:

Owner - read write execute

Group - read write

Other (or world) - read only

2) Give the chmod command to change permissions on file2 to give:

Owner - read execute

Group - read execute

Other - no permissions

and set the setuid bit

3) Give the chmod command to change permissions on file3 to give:

Owner - read write execute

Group - read execute

Other - execute

                4) Give the chmod command to add read permission for the group ownership of file4 but without modifying other existing
                     permissions.

                5) What is your standard file creation mode (type umask to see)?

                6) What umask would you use if you wanted all of the files you created to have by default

rwx for owner

rwx for group

read only for other

7) What is chown used for?

Write a Basic Script

Write a script called getinfo

This script will take one command line argument which will be the name of a program (additional arguments can be ignored).

This script will then run whatis, whereis and type -a providing the same argument that was passed to the script getinfo. Here is an example where I call getinfo on tiglon three different times:

toddj@tiglon:~$ ./getinfo type
type            type (1)        - write a description of command type
type            type (1)        - write a description of command type
type: /usr/bin/type
type is a shell builtin
type is /usr/bin/type


toddj@tiglon:~$ ./getinfo ls
ls              ls (1)          - list directory contents
ls              ls (1)          - list contents of directory
ls              ls (1b)         - list the contents of a directory
ls              ls (1)          - list contents of directory
ls              ls (1b)         - list the contents of a directory
ls: /usr/bin/ls /usr/ucb/ls
ls is /opt/gnu/bin/ls
ls is /usr/bin/ls
ls is /usr/ucb/ls
ls is /usr/ucb/ls
ls is /opt/gnu/bin/ls

toddj@tiglon:~$ ./getinfo cd
cd              cd (1)          - change working directory
cd              cd (1)          - change working directory
cd: /usr/bin/cd
cd is a shell builtin
cd is /usr/bin/cd

When getinfo is called with no arguments it will print the usage message as below:
```
toddj@tiglon:~$ ./getinfo 
Usage: getinfo COMMANDNAME
please try again...
```
(Notice that when getinfo was called without any arguments there was no additional error messages (for example, "usage: whatis keyword ..." or "whereis [ -sbmu ] [ -SBM dir ... -f ] name..."). Therefore this script will need to check that it was called with at least one command line argument.
I recommend writing this script using bash but you can use any of the following if you prefer sh, csh, tcsh, ksh. or perl.
To run the script you will need to have execute permission on it and have it in your PATH (or give the path like I did above ./getinfo).
Please include one line of documentation

# getinfo script - written by YOUR NAME

(You can document it more if it helps you but one line similar to above is all I care about).
Include a print out of this script with your turn-in