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Systems Administrator Test
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Please answer all questions to the best of your ability. If you don't know
the answer to a question, state possible options about how you would attempt
to obtain the answer. Be as explicit as possible with your answers. You are
encouraged to write small scripts in whichever language you feel comfortable
where applicable.
Please read the test in its entirety before answering any questions.
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1. You execute 'ls -l' on a directory. Where you would normally see the
owner's name, you see a numeric ID. What circumstances could contribute
to this behaviour?
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2. You're curious as to the size, number, and type of swap devices on a
machine. Where might you find this information? Assume a Linux system.
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3. Explain the role of the environment variables TERM, PAGER, VISUAL, and
SHLVL.
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4. Assuming a Bourne-compatible shell, what would happen if you executed
the following commands? The commands are in no particular order.
a) cd -
b) echo ${DISPLAY:-SHELL}
c) ^-t^-r
d) ls -l !$ 2>/dev/null >>/tmp/thisfile
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5. a) Bill has recently left the company. His sources are kept under the
directory /usr/src/bill. Fred is going to take ownership of the
project, but wants to allow others to be able to modify the files.
How would you change all the files to be owned by 'fred', group
'staff'. Files should have owner, group, world read, owner/group
write; directories should have owner, group, world read/traverse,
owner write.
b) Describe the consequences of adding the following permissions.
Assume the permissions are granted one after another.
*) All directories get group write.
*) All directories have the sticky bit set.
c) Alter your answer to part A to reflect the above changes.
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6. To what should the root user's umask be set? Why?
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7. Under what situation could the following sequence of commands produce
the following output? How would you confirm the cause?
chainsaw% cd /tmp
chainsaw% ls -lh thisfile
-rw-r--r-- 1 root root 4.0M 2008-01-15 19:26 thisfile
chainsaw% cp thisfile thatfile
sh: cp: no space left on device
chainsaw% df -h /tmp
Filesystem Size Used Avail Use% Mounted on
/dev/sda8 4.0G 281M 3.8G 7% /tmp
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8. You find a script that has been misbehaving and not cleaning up its
temporary files. In the directory in which these temporary files are
written, you see over a million distinct files. Attempting to delete
them results in this:
chainsaw% rm .ws*
rm: argument list too long
The directory in question also contains several subdirectories which
contain important data, as well as files that are not of a temporary
nature. How would you solve this problem and delete only the temporary
files without removing the upper-level directory, or any files in any
subdirectories beneath?
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9. What are the RAID levels natively supported by the Linux kernel, and
what is the command and syntax to create 4-disk RAID 5 array? Assume
2.6 series.
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10. You have two options for purchasing a quad-port gigabit ethernet
controller: a PCI-X adapter or a PCI Express x2 adapter; all other
features remain identical. The target machine has both PCI-X and PCI
Express slots available. Which do you choose, and why?
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11. Under what situation would you choose the following types of hard
disks? Which brand of hard disk is your favorite, and why?
a) SATA
b) SAS
c) IDE/ATA
d) SCSI
e) Fibre Channel
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12. A user attempts to log in to their GNOME desktop, but the login process
stops halfway through and the user is sent back to the GDM login screen.
a) Where would you begin to look for the cause of this issue?
b) Without root access, how would you get in and solve this problem?
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13. To reduce the number of moving parts in a system, you decide to boot a
machine from flash memory instead of a traditional disk.
a) Which filesystems would you have to dynamically create on a RAM disk
to avoid flash fatigue?
b) What other caveats exist on a machine booting from flash in this
manner?
c) What would you do differently?
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14. Explain the modfications necessary to /etc/syslog.conf to cause syslogd
to log all messages to a remote syslog server as well as the local
system logs.
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15. You forgot the root password to a system that's been running for several
years. After an accident at the foosball table renders the server without
power, you need to log in to restart some services that weren't started
on a reboot. Explain how you would go about solving this problem and
recovering the root password. Assume a Red Hat-compatible Linux.
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16. Explain the benefits of a system with multiple partitions for the various
standard top-level directories. Which filesystem do you like best, and
why?
a) Which of these top-level directories would you normally separate from
the root partition?
b) Assuming a 36 GB disk, how large would you make each partition?
c) What filesystems would you use for each partition?
d) What special mount options, if any, would you use, and where?
e) Devise a situation where using LVM may be an advantage.
f) Devise a situation where using LVM may be a disadvantage.
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17. This question expects a string of Vim commands. Use as few as possible
to answer each subpart. Type a literal Enter to signify the end of a
command which ends with the Enter key. Use ^C, ^H, etc. in place of
control characters. Use ^[ (then press enter) to signify the ESC key.
In Vim, how would you:
a) change the first three words on line 23 to the phrase, 'how now
brown cow?' (the linebreak is not part of the phrase)
b) change every occurrence of the string, 'let me in', with the string,
'you stay out'.
c) Quit without saving changes.
d) ...
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18. a) To what does the acronym, "IPMI," expand?
b) What use is IPMI?
c) What common features does IPMI provide?
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19. Edit the following BIND 9 zone file to add two hosts, chatchi, with IP
address 10.24.16.26, and brainy, with IP address 10.24.16.100. Correct
any errors that may be present in the zone.
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$ORIGIN .
$TTL 3600
ex.int IN SOA ns1.ex.int hostmaster.ex.int. (
2008011400
10800
900
3600
3600
)
NS ns1.ex.int.
NS ns2.ex.int.
MX 10 mail.ex.int.
$ORIGIN ex.int.
chainsaw A 10.24.14.200
chainsaw MX 10 mail.ex.int
dev CNAME chainsaw
hefty A 10.24.14.201
lazy A 10.24.14.214
monster A 10.24.14.227
stupendous A 10.24.14.222
dev A 10.24.14.247
boredom A 10.24.14.261
stupendous A 10.24.14.223
lookout A 10.24.14.227
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20. a) What errors are (or were) present in the above zone file?
b) In the Start of Authority section, there are five numbers. What, in
the order they are listed, do these numbers mean?
c) What additional steps would you perform after editing the forward
zone file above?
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21. a) What dotted quad netmask does the IP address 10.23.22.240/23 use?
b) What would the network address and broadcast address be for the
above IP range? How many usable IP addresses are there?
c) Can you assign an address to a Linux interface using this VLSM
nomenclature? If so, how would you do it?
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22. a) What is variable-length subnet masking and why is it important?
Hint: it was created to enable CIDR.
b) Which RFC 1918 reserved address range should typically be used on
a corporate network, and why?
c) Why might a corporate network have more than one RFC 1918 range
in use?
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23. Could the IP address 10.23.23.0 ever be a valid host address? If so,
explain a situation where this may be possible.
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24. To what does the term, "Wide area network," refer? In what situations
might a wide area network be useful?
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25. Explain the following Bourne shell code, and why it should NEVER be
executed.
:(){ :|: & };:
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XX. What is the ultimate answer to life, the universe, and everything? Who
discovered this answer, and how long did it take?
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13.
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If you got here without answering a question, great. From a terminal, execute
the command, '/opt/scripts/begin-test.sh'. Save this file when you begin the
test, and save it after each subsequent answer to a question. If you go back
and edit your answers to a question after you've saved it, that's fine. Just
save it again. Send SIGINT to the command when the test is complete.
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