Route emails in a perl script

[James R. Ferguson]

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@allanm77 wrote:
Have another question about the original perl script (from above), I want to use that on three to four different files -
/var/tmp/email & /var/tmp/email_new & /var/tmp/email_newer
with same logic and probably send to different userids with different subjects.
I tried to keep that in the same script but struggled with die statements which used to close the program if it couldn't find the one of the file.

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Currently you 'die' (with the reason for the death) if you can't open a file.  That's one way.  I would construct your 'open...or die...' like this, though:

...
my $HM_name = '/var/tmp/email';
open NM, .'<', $NM_name or die "Can't open '$NM_name': $!\n";
...

You can also test for the presence of a file and only if present, open it:

if ( -e $NM_name ) {
    open NM, '<', $NM_name or die "Can't open '$NM_name': $!\n";
}
else {
    ...
}

Notice how we defined the file name as a variable for consistent use throughout, too.  If it's wrong in one place, its the same "wrong" everywhere :-)

In the second example code where we test for file existence we are ignoring a race condition where a file does indeed exist and the test is satisfied, but the open fails (and you die) because when that's atttempted another process has removed the file.  I don't believe that you need to worry in a case like this, but you should be aware of the potential if only in the abstract.

Regards!

...JRF...