Introduction Unix
Homework 4

1. What are the permissions for your home directory set by your system
administrator? What command did you use to answer the question? Show your
session.

2. Consider the following files (or directories): /, /etc/passwd, 
`which df`, ~, .bash_profile (in your home directory). Show the long
listings for these files.  What is the meaning of each field in the output
of the ls -l command?

3. For files and directories given above, show permissions as octal numbers.

4. Change directory to your home directory. If there is not a directory in
your home directory called temp, create it.  Set permissions for ~/temp to
execute only and run the ls -ld temp command. Now execute the ls -l temp
command. What happens? Does it make sense to you? What are the minimum
permissions required on a directory for the ls -l temp command to execute
successfully. Set permissions for the temp directory to the minimum required
and re-execute the ls -l temp command. Show your session.

5. Create a new directory.  Use the ls -ld command to determine the
permissions of the directory.  Use the id command to determine your current
group id number (gid).  Now execute the command newgrp cmst270 and create
another directory.  Use the id command and ls -ld for the new directory to
determine all the effects of the newgrp command.

6. Use the wc command with the /etc/passwd file to determine how many
accounts are your system.  What does the head /etc/passwd command tell you
about the first several accounts listed in /etc/passwd?  Use the command 
cat -n /etc/passwd | more  
to determine the line number of your entry in the file.  Now combine the
head and tail commands to list just the line for your account.  Do you know
of any other commands that will display the content?

7. Execute the command getent passwd. For your user id, execute the getent
passwd userid.  How does the getent command relate to the contents of the
/etc/passwd file?  When do you think it would be better to use the getent
command instead of the /etc/passwd file?  You may want to read the man page
to determine this.