IT Job Interview

Not just give a list of shells you have used, try to describe some of the key features of the shells, showing you have the real experience on them.

“I got used to the Bourne shell for early versions of Unix.  Then I become accustomed to the Korne shell and happen to like it very much.   It has more functions than that in vi or Emac.  The interactive command line editor is so wonderful.  It has built-in environment variables which allow for a customized environment.”

Then, a follow-up question might be, what’s your experience in shell programming?  A good answer is to give a few examples about what scripts you have written to accomplish what tasks.

“Having a number of years’ experience using the shell, I have become very accustomed to shell programming.  Script writing is almost second nature and I could apply the technique to all phases of systems administration.  I have written scripts that perform automatic system backup during low CPU utilization hour.  I have written interactive scripts which help to restore files to the system, scripts which can add or remove a user from the system, and xripts for new system installation.”

‘Cron’ is a command whose services are initialized when the system is brought up in multiuser mode.  When loaded, it executes commands at specified dates and times.  It runs in background as a clock daemon until it is killed either by the ‘super’ user or when the system shuts down or ‘init’ed in a mode that kills it.  The cron daemon wakes up once a minute to see if anything needs to be run.  Heavily loaded systems many expect a delay of a few minutes.

These commands are specified in a specially formatted file in the ‘/usr/spool/cron/crontabs’ or ‘var/spool/cron/crontabs’ directory.  The file that executes ‘super’ user commands can be found in the root file.  Regular users may also submit jobs to ‘cron’ deamon as long as they have ‘cron’ permission.

Obviously, the interviewer wants to know if you have any hands-on skills on UNIX network troubleshooting.  If you do have the experience, you must have used the following handy tools:

Netstat – Shows the status of the network.
Ping – Sends packets to a destination address and tracks the performance of packets round trip.
Spray – sends packets (like ping_ but, instead of one packet, it sends a burst of packets for greater duration, putting a simulated load on a network component to better test its communications.
Ifconfig – Can be used to ascertain useful network information as well as to configure the network port.
Etherfind – gives network information about all network traffic passing through the network connection.