You first need to choose a scheduler. cron is the most usual, being a standard feature of the O/S, although autosys provides more advanced functionality. There are plenty of others too, like Tivoli Workload Scheduler.

Suppose it's cron, then you would do something like

0,15,30,45 * * * * /home/projectX/fred.pl >fred.out 2>&1
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and put something like this in fred.pl

my @found = glob '/data/projectX/ftpin/*'
  or exit;
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