[sf-lug] favorite interview questions

Michael Paoli Michael.Paoli at cal.berkeley.edu
Sun Apr 25 11:20:17 PDT 2010

Here's a set of questions/answers/topics/keywords from a few different
sources - including also an outline of topics/keywords I typically use
as a basis of questions.  Most of them are for Linux/Unix system
administrator type positions, some are for manger positions.  Some of
the questions/"answers" may be outdated/obsolete, flavor specific, or
somewhat or perhaps even completely wrong.  I generally tossed in enough
context to make each item generally sufficient to be stand-alone, then
squashed them to a single line, randomized the order, and then
reformatted to make reasonable length lines, added an emty line between
each item ... so the formatting will be rather funky at least in places.

Have fun :-)

... I also tossed in a fair bunch of comments at the very end


Given the following answer these questions: cdrom is attached at id 6
and working fine.  the 5.3 base cd with installation tools is in the
player the /stand directory on the cdrom contains the following files:
sashARCS, sasIP12, sashIP22, sashIP6, fx.ARCS, fx.IP12, fx.IP22,
fx.IP6.  the hinv of this system looks like this: Iris Audio Processor:
version A2 revision 4.1.0 1 100 MHZ IP22 Processor FPU: MIPS R4010
Floating Point Chip Revision: 0.0 CPU: MIPS R4000 Processor Chip
Revision: 3.0 On-board serial ports: 2 On-board bi-directional parallel
port Data cache size: 8 Kbytes Instruction cache size: 8 Kbytes Main
memory size: 48 Mbytes Integral ISDN: Basic Rate Interface unit 0,
revision 1.0 Integral Ethernet: ec0, version 1 Integral SCSI controller
0: Version WD33C93B, revision D Cdrom drive: unix 6 on SCSI controller
0 Disk drive: unit 3 on SCSI controller 0 Disk drive: unit 1 on SCSI
controller 0 Graphics board: Indy 8-bit Vino video: unit 0, revision 0,
IndyCam connected What would the commands be for booting standalone
shell and then standalone fx be if I then said that this system wasn't
supported in the multi-architecture sash/fx (namely that the *ARCS*
files didn't work)?  -  What commands would you use to boot standalone
shell and after that standalone fx be if they were supported in the
multi-architecture sash/fx?



Give candidate employment application, business card(s) and mailto
address, ask for reference information, copy of resume

Describe a situation where using NIS would NOT make sense among a group
of machines. Why is NIS NOT appropriate in your example?

(shell) $* $# $@ "$*" "$@" ' \ ` " $? shift signals

How would you generally attack responding to a security incident?

Managers get a call from operations if the oncall person does not
answer the page.  What do you do if you receive such a call.

What is the name of the uucp control file that contains site
information that lists 'site name', 'dialer type', 'baud rate', 'phone
number', 'login', and password?

can you tell me the basic commands to examine and manipulate acls?  Can
you describe the syntax?


Lets say a E10000 running internet banking just crashed and all of the
local admins have left to work on the issue. What is your roll as

And what must be changed in the BIND configuration files so that the
slave servers will pull the new zone info?



boot single user mode

replace all occurenses of foo with bar in file, use any POSIX/SUS
standard means

IP address, netmask, calculate subnet address how?



Are you comfortable working in an event-driven environment?

What is the /etc/magic file used for?

write down the seven backup levels you would use each night for dump to
do a full backup on sunday and then each night backup all files on the
disk that have been modified since the last full backup.


What is the name of the configuration file that directs a DNS client to
its nameserver?

Write down the seven backup levels you would use each night for dump to
do a full backup on sunday and then each night backup just the files
that have changed from the previous night


An executable script file called "daisy" is owned by a user called
"barney".  What is the effect of the following command?  chmod 4711

describe the basic filesystem permissions on Unix

Do you prefer working independently, or on a team? close/loose
supervision? In what sort of work environment are you most productive,
and why?

awk / sed

What salary are you interested in?

server ip=, netmask=, and the gateway is at  The interface is plumb/up.  Specify the command to add a
default route for the gateway.

(abc,rwx)(%.data,r-x)(%.folks,r-x)(%.%,---) /stuff

What are some files and directores that must have world read/write?
How do you secure them?

What would you do if you see an admin reading a technical book or trade
magazine during office hours?

What command(s) enable(s) Veritas to access newly added drives (i.e.
disks added to a live system)?

Describe a situation where using NIS would make sense among a group of
machines. Why is NIS appropriate in your example?

You have been asked to setup a NIS Master server on moe. List the steps
you would perform and commands you would execute.


Consider the following situation:  you have a rather large directory
tree structure (/a/bigdir) that is taking up too much space in the file
system where it is currently located.  You have a lot more space in the
/b directory, which is the mount point for a much larger file system.
In the space below provide the unix command(s) you would use to
relocate the /a/bigdir directory tree structure over to /b in a way
that would preserve all of the information in the original (same file
dates, ownerships, permissions, symbolic links etc.)

On a 'client' system, what is the command and syntax for listing the
exported NFS partitions from a server named "moe"?


non-root filesystem containing only application and/or user data is
gone due to drive failure, what steps do you take to recover?

How do you solve: "network connectivity is too slow"

(abc.%,rwx)(%.data,r-x)(%.folks,r-x)(%.%,---) /stuff



Name the three main disk partitions or directories that are required,
as a minimum, for UNIX to boot and run?

drwxr-sr-x - what would the 's' indicate?

Databases in general?



/proc filesystem

A directory called "/scratch" is owned by "root".  What is the effect

nice / priority

Note relative quality of oral communication skills, general quality of
interaction with interviewer(s) (think in terms of communication of
procedures, oral reports, interaction with groups, users, guestimates
of quality of interaction and exchange in general)

test / [


What do you consider your greatest strength?  Weakness(es)?

What is the Solaris command(s) to add users philo and yubby to the
access list for file stump (both with read and execute permission only)?

How do system backups fit into creating a secure environment?

C programming experience/questions

What commands are utilized to view configuration and configure Sun
Storage Arrays and Sun Network Arrays(ie ssa's and photon's)?

Show the command and its syntax to create a symbolic link of
"/usr/home/mystuff" to "/data1/mystuff":

Today we have weekly staff meetings and a separate meetings with the
leads and management. What are your feeling of other meeting with you
staff across other locations?

What is(/was) your present(/most recent) salary?  next prior - work
done, why left; ...

Tell me about a challenging problem or project you had, the work you
did on it, and the results.

implications of the following command? chmod 01777 /scratch

What command and options will list network routes currently in use?

Explain the difference between the automounter and the traditional way
of mounting NFS based file systems

As system administrator you have many responsibilties. List some ways
you can improve your site's system security

drwx---rwx  15 angel  folks  1024 May 22 10:36 /people/angel

In the following command, what does the option "p" refer to?  tar xvpf


How do you work with and handle short-term situations where there's too
much to do for the time available to do it?  What if it is or becomes a
longer-term situation?


User complains, "The system is crawling!" - where do you start?


How do you feel about user support?

What salary would you require or would you expect us to pay you?

Performance & system usage

Explain the components of the following output: % ls -ld rh4 drwxr-xr-x
  4 jerryh  devel  4096 Jul 19 11:53 rh4

drwxr-x---+ 15 abc  folks  1024 May 22 10:36 /stuff

What are the three network config items that need to set for a server
to be pingable from other hosts (even from different routes/subnets)?

Volume Manager

drwx---rwx  15 angel  folks  1024 May 22 10:36 /people/angel



How do you solve: many users on multiple machines?

You have been asked to setup a NIS Client server on a client machine
named larry. List the steps you would perform and the commands you
would execute.

What command will remove this symbolic link?

Situation: You have two machines named calvin and hobbes. You have
received a HP4 SIMX postscript printer to be attached to the parrallel
port device /dev/plp on calvin.  The input filter for the printer is
/usr/local/bin/psif The output filter for the printer is
/usr/local/bin/psof Accounting and log information should be placed
under /usr/adm The spool directory should be placed in the directory
/usr/spool/lpd The full name of the printer should be ifsmhp4simx with
a short name of ifsmps Create the local printcap entry on calvin for
this printer Create the remote printcap entry for the printer on
hobbes. Assume the same name as above and locate the spool directory in
the same area In addition to the printcap entry on hobbes what else
must be done to allow hobbes to print on calvin.


at / batch / crontab

What interested you about the position we have open?

drwxr-x---+ 15 abc  folks  1024 May 22 10:36 /usr2

If you've just freshly loaded a clean, out-of-the-box installation of a
vendors operating system onto a newly received Unix machine, what steps
do you go through to check and clamp down on the systems security?

What file (on Solaris) contains entries that modify kernel parameters
(for tuning, etc)?

Explain in your own words, what miniroot install is, and how it works
(be detailed please).  Explain in your own words, what a standard
install is, (standard install being from a root window on a machine in
multi-user state), and how it works (again please provide detail).  How
are they different and when would you typically use each one?



Describe position to candidate: general work, responsibilities;
systems; environment in general; <company>, benefits, etc.
(show/provide benefits information)


Do you expect everyone to be in their desk ever hour and account for
all time.

What command lists the amount of space used and available on a mounted

boot single user mode from CD-ROM

Your first week of work you notice an admin has not been in the office
several mornings. What do you do and what do you think?

Tell me about your most recent position: your responsibilities, what
you liked and didn't like about the job?  Why did/are you leaving?

An NFS server named "moe" has an exported directory named "/data1".
Show the command and its syntax for attaching a client to this
directory as "/moe/data1":

Unix system call questions

environment vs. shell variables

(dump) A new type of tape called DLT is available and will hold over 10
Gigabytes of data (10,000,000,000). You must calculate the parameters
to use for density and for the distance in feet of the tape.  Remember
the ratio of density to distance should not be more that 100 to 1.

100 Full

What's the SGID bit do?  On a directory?  A file?

How do you know if an admin completes a workflow request.

remove file '-rf *'

What command flushes all pending disk I/O buffers and updates the file
system superblock?


When would you be available to fill this position?


What do you think you'd like most about this position?  Least?


are you familiar with acls?  Have you worked with acls?

What is the name of the program or process that checks file system
integrity during system boot?


Consider the following 'ls -ld' output line and explain the elements
below: drwxr-sr-x  2 jerryh  devel  4096 Feb 12 12:28 work


A directory called "/opt" contains a subdirectory called "hdata".  Show
the syntax for the tar command that will create a tar file of all the
contents of "hdata" called "h.tar" in "/tmp":

(and/or - as/if applicable:) I see you've changed jobs a lot in the
past, why's that, and why would you stay here?

hard link; symbolic link; multiple hard links

How do you solve: the filesystem's full

How do you solve: mail: Cannot open savefile


Assume we have two users (moe,larry), each with there own machine
(named the same as each user). The files of each user reside on their
workstation. They occasionally must use the other person's machine and
have decided that it would make sense to automount the files when they
login to the other machine. On each machine they have a seperate disk
with their respective user files that is the device /dev/dsk/dks0d1s6 .
  For both machines give me a the /etc/fstab file and the automount file
needed to make this work. In addition, please list the automount
command that would needed.  Assume the automounter does not work
properly. They have decided to use tradional NFS, show the entries in
the fstab file and the commands to mount the files.

How do you know your staff is actually performing the task scheduled
for 2 am.

What file specifies the order in which NIS servers are searched for, in

Explain how you would use 'tar' to copy a full directory tree to
another location.  Say you have 'newdir' in /tmp and you want the tree
moved to /home/fred.  What if /tmp/newdir is on a different server that
doesn't mount /home/fred?

How do you handle "problem users"?

What is the name of the uucp control file that contains modems
available to processes on a system?

non-broadcast NIS client mode?

You wish to export the veritas diskgroup "yubby".  What command and
options would you use to accomplish this?


The pretend situation is that you have a hundred or so files in the
current directory with '.F' suffixes and your new fortran compiler
wants these all to end with '.f' instead.  In any shell you prefer,
explain how you would rename all of these files to keep the first part
of each name but change the suffix to the lower case '.f'.


What do you enjoy doing most?  Least?

sh/ksh/csh/POSIX shell, etc.

root filesystem's gone due to drive failure, what steps do you take to
recover beyond those for non-root filesystem?

what would you like to be doing 2 years from now?  5?

What's the sticky bit do?  On a directory?  A file?

What file lists the name, type, and port number for socket-based
daemons or applications?

rename file

What is the difference between using standalone fx and fx on a machine
that is in multi-user state? How are they different and when would you
typically use each one?  Again, please use your own words and provide
enough detail.

When you run into a problem, what approach do you usually take to
resolve it?

If a team lead from another city calls stating a project is having
several problems but the lead has everything under control. What do you

How do you solve: lots of "little" backups on lots of Unix machines?

What are the two files that need creation/modification on a Solaris
system, to enable the system to use DNS for IP name resolution?

The configuration files for a DNS server have just been changed.  If
"named" is currently running with a PID of 137, show the command and
its syntax that will inform "named" to reread these files.


What are some of the common hazards/errors programmers and vendors make
with SGID/SGID programs?

What's the SUID bit do?

What command(s) enable(s) Solaris to access newly added drives (i.e.
disks added to a live system)?

fair bunch of comments:

USENIX/SAGE Core Job Descriptions:
useful for a relatively common description of various "levels", and also
as reference on sets of skills likely to be expected for various levels.

I typically work from mostly from an "outline" of
topics/questions/answers.  Much of the stuff could be question, or
answer, e.g. explain <whatever> and when/where one would typically use
such, ... or I give scenario or question to which that particular
<whatever> would generally be the answer or solution.

Typical interview style :-> - I typically forewarn candidates that I'll
ask a lot of questions, and don't feel at all bad if they can't answer
about half of them or so - I tend to jump around and adjust difficulty
level to a large extent, to try to find about where the boundary is
between what they do, and don't know - makes for interesting/challenging
interviews ... and also finds knowledge/experience level relatively
quickly and fairly accurately - I also mix in somewhat randomly
particularly harder, and easier questions, to see if I'm getting
relatively consistent results relative to my thus far guestimation of
still level.  This technique seems to work rather to quite well on
smaller scale (relatively small numbers of candidates). ...

For larger numbers of candidates, some type of (quite) standardized test
can be very useful - that can be quite effective at providing an
apples-to-apples comparison across large number of candidates (typically
not a "final" step, but often quite useful in screening/filtering and at
least preliminary ranking).  My "typical interview style" noted above,
doesn't do quite as well on the "apples-to-apples" criteria, as no two
candidates get precisely the same set of questions (but there is
generally at least enough similarity in areas covered and noting of
responses, to reasonably differentiate among candidates).

> Date: Sat, 03 Apr 2010 09:50:16 -0800
> From: jim <jim at well.com>
> Subject: [sf-lug] favorite interview questions
> Cc: sf-lug at linuxmafia.com
>    what are other standard interview questions?

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