Emergency UNIX and Linux Support

Hello

I wrote a nice Perl script that is intended to find and copy some files when getting a TERM signal. Now I wanted to make a shell script that starts/restarts the Perl script if it crashes/ends because of errors and make a log of all output the Perl Script gives. The problem is that it won't write any output to my logfile
Here is my Shell script:

Code:

#!/bin/sh

pidcheck=`pidof perl | grep -c [0-9][0-9][0-9][0-9]`
while [ $pidcheck -ne 0 ]
do
        kill -9 `pidof perl`
done
echo "\n------------------------------\n" >> log.txt
date >> log.txt
echo "\n------------------------------\n" >> log.txt
while [ 1 -eq 1 ]
do
        `perl handler.pl >> log.txt`
        echo "Perl-Script crashed, restarting..." >> log.txt
done

I think it would write if I don't put the `` around `perl handler.pl >> log.txt`, but then I can't send any signals to my perl script :/

Can (maybe) someone help me? ^^' thanks in advance and sorry for my bad english

doesn't anyone have an idea?
pleaaase I need the code within the next 3 days and I really don't know how to get it working (neither does google)

just joined the forum. and this thread is very old as well.

but would like to make a comment if some searcher can get this helpful.

you can schedule your script in cron to run every minute
and in your perl script check at the starting if another instance of script is running.
if so ...quit. else continue..


dont tell me that you need a code as well for this.. its pretty simple and wont take more then 3 lines..

Thank you for your reply but that wasn't my problem...
My problem was that I couldn't log anything
And I asked for help to finish my code, not for the code itself
And btw I don't see why cron should help in my case? I needed a script making something when I send a TERM signal, not a script making something at a specific date/time...

okay, so you were actually looking for a graceful shutdown or termination.
or technically saying a interrupt handler..


you probably could use
$SIG{'INT'} = 'interrupt_handler';

sub 'interrupt_handler {
print("Script got a termination signal, shutting down...!\n");
exit; # or may be you want to continue ignoring the signal then dont use exit.
}


I hope that would help.

Not really shutdown - more a sighandler.
I didn't wanted to end my script but to make something (f.e. write "hello" into a text file).
[edit]: yeah I used that in my script but there was a problem that my script wouldn't catch any signals when I'm logging it via the script I posted... I'm sorry it's a bit complicated to explain >_< ...
I'm sorry I can't test your solution because I don't have the script anymore >_>
But it's nice that you answered for anyone finding this when searching for it!

Maybe this is partly about logging on a buffered fd/FILE* like stdout, not unbuffered stderr, and no periodic flush(), with lost output when the script hangs and has to be killed? Logging through a pipe chain has a similar latency problem with potential lost output. One workaround for infrequent logging is to log by

Code:

system("echo 'Message' >>log_file")

or

system("date '+%Y-%m-%d %H:%M:%S Message' >>log_file")

or equivalent calls in perl using ``.