Using a Perl Script To Execute a Linux Command

kgill has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,

I am a Unix/Linux server administrator for a company, and I am a "newbie" in the purest sense of the word in terms of Perl. I'm able to make Perl files using the VI in Unix. I'm trying to get two scripts running--one to stop or start my database server that is running Oracle and one to start or stop my application server that is running Oracle. Currently, I'm entering the commands manually, but I would like to schedule the scripts to run every Friday to shutdown and Monday to startup.

A few of the commands needed to start and stop the database and application servers involve changing directories to execute the commands. How can I write a nice, clean script that can do this?

Thanks, Kris

P.S. Here's a mock-up of what I'm trying to accomplish:

SHUTDOWN

APPLICATION SERVER

login <user>

cd /opt/SIV/inst/apps/SIV_<servername>/admin/scripts ./adstpall.sh pass/pass

login <user>

cd /opt/SIV/db/tech_st/10.2.0 . ./SIV_<servername>.env

sqlplus / as sysdba

shutdown immediate

exit

lsnrctl stop VIS

A similiar script would be needed for the startup.

Comment on Using a Perl Script To Execute a Linux Command

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Re: Using a Perl Script To Execute a Linux Command by MidLifeXis (Monsignor) on Jan 23, 2008 at 16:39 UTC
Just because you bought a new hammer does not mean it is the right tool for putting in a screw. I would use a `cron` script, probably as root (or another user using sudo), and call the various stuff as the appropriate user from a shell script. To use perl, you would need to handle loading the env files, talking to the sqlplus binary, and other things where there are already examples to do these scripts from a shell. --MidLifeXis	[reply] [d/l]
Re^2: Using a Perl Script To Execute a Linux Command by kgill (Initiate) on Jan 23, 2008 at 16:51 UTC
Good point. Thank you for your response. I'm looking at doing this with cron right now. Thanks again, Kris	[reply]
Re: Using a Perl Script To Execute a Linux Command by igelkott (Priest) on Jan 23, 2008 at 16:47 UTC
What you ask isn't trivial (IMHO). To start, you might look into Expect to send commands to launched programs (like sqlplus). There are other ways to do this but it seems to fit best with what you've outlined here. It might be easiest to have most of the startup/shutdown controls in a Perl script local to that machine so your local script just needs to login and start the remote script.	[reply]
Re: Using a Perl Script To Execute a Linux Command by Anonymous Monk on Jan 24, 2008 at 08:05 UTC
Use system() for the commands (or IO::Open2 if they need IO) and chdir() to change directories. For sleeping, you could either ignore the time it takes to execute the commands, use the start/stop times to put in a correction (which will gradually increase the longer your script is on), or a time-$time like construction employing the % operator. Or you could use a cron script, which would probably be a better choice.	[reply]