====================
Lab 7 sample answers
====================
- Ian! D. Allen - idallen@idallen.ca - www.idallen.com

Copy all the numbered questions labelled "ANSWER:" below into the
lab07answers.txt file and, below each question, give your command line
and answer to the question in the file.

For full marks, whenever you are asked for the output of a command,
include the command that generated the output in your answer as well.
Always include the command lines along with the output of the commands.

15) What file name contains the default run level for Linux?  ANSWER:
    /etc/inittab

16) What run level does this "White" UML machine default to at boot?
    Give a command line that selects and displays the line containing the
    default run level from the associated file, along with its output.  ANSWER:
    # grep initdefault /etc/inittab
    id:2:initdefault:

17) Note that the "White" UML machine delays for 10 seconds during the
    boot.  Locate the associated start-up script symbolic link located
    in the start-up directory of the current Linux run level for the
    "White" UML machine.  Show a long listing of the absolute path
    to the delay start-up script symlink (not to the script itself).
    (The symlink is the only entry in the whole run level directory;
    it is dated 2006-01-10 09:10) ANSWER:
    # ls -l /etc/rc2.d/*
    lrwxrwxrwx  1 root root 15 2006-01-10 09:10 S99delay -> ../init.d/delay

18) Show a long listing of the absolute path to the delay start-up script
    itself (to the actual script, the target of the symlink, not to
    the symlink).  (The real file is dated 2005-03-08 21:29.)  ANSWER:
    # ls -l /etc/init.d/delay
    -rwxr-xr-x  1 root root 407 2005-03-08 21:29 /etc/init.d/delay

19) Remove the delay symlink from this run level of the "White" UML
    machine using an absolute pathname to the symlink.  (Only remove the
    symlink; don't remove the actual script!)  Give the command line,
    including the absolute pathname of the symbolic link you removed:
    ANSWER: rm /etc/rc2.d/S99delay

20) Reboot your "White" UML machine (not your host VNS!) using
    the console command "shutdown -r now".  Make sure the "White"
    UML machine reboots without the 10 second delay.  How long does a
    UML shutdown and reboot take?  ANSWER:  varies, e.g. 40 sec

21) VNS is Knoppix-based, which is a Debian-based Linux system.
    In which Debian directory does your text say we put "Local startup
    scripts" that will run at boot time?  (ALN Table 4.1 p.81) ANSWER:
    /etc/rc.boot

22) Which control script in /etc/init.d/ is responsible for running the
    executable scripts in the above directory?  (Look for the above
    directory name in all the scripts.  It appears on two lines in
    one script.  The script name should match the name of the Debian
    "Startup control script" in ALN Table 4.1 p.81).

    In other words:  In /etc/init.d/ there is one special script that
    is responsible for running all the boot-time start-up scripts and
    for running the "Local startup scripts".  First, find the Debian
    name of the directory containing the "Local startup scripts".
    (You just did this in the previous question.)  Look for that local
    startup script directory name in all the scripts under /etc/init.d/*
    in your White UML machine.  You will find only one file that mentions
    this directory, on two comment lines.

    Give the command you used to find the name in all the init.d scripts,
    along with the two lines of output of the command: ANSWER:
    # grep rc.boot /etc/init.d/*
    rcS:#   For compatibility, run the files in /etc/rc.boot too.
    rcS:#[ -d /etc/rc.boot ] && run-parts /etc/rc.boot

23) You will note that the two lines of script comments that you find
    above in the White UML machine are commented out as being "for
    compatibility" - the UML machines do not use the old rc.boot
    method of running boot-time start-up scripts.  The FOR loop above
    those two lines, in the same control script file, shows in which
    directory modern boot-time start-up scripts should be placed.
    (The comment at the top of the file also gives its name.)  What is
    the name of the current boot-time start-up scripts directory, into
    which symbolic links are placed to each boot-time start-up script?
    Give a long listing of the contents of this directory (it contains
    a directory, a file, and three symlinks):  ANSWER:
    # ls -l /etc/rcS.d/
    drwxr-xr-x  2 root root 1024 2006-01-10 08:45 orig
    -rw-r--r--  1 root root  701 1997-09-01 08:48 README
    lrwxrwxrwx  1 root root   18 2006-01-10 09:10 S00umlsetup -> ../init.d/umlsetup
    lrwxrwxrwx  1 root root   18 2006-01-10 09:10 S02umlcolor -> ../init.d/umlcolor
    lrwxrwxrwx  1 root root   20 2006-01-10 09:10 S40networking -> ../init.d/networking