my $info_desired_filepath = glob('/home/myfiles/day_of_year/'.$day_of_interest.'/data/desired_file.txt');
Since you only expect the glob to return 1 file, that line can be simplified as: 
    my $info_desired_filepath = "/home/myfiles/day_of_year/$day_of_int
+erest/data/desired_file.txt";

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the code is something like:
Show your exact code. Reduce your code sample to narrow your problem down, if need be.

Basic debugging checklist

In reply to Re: Globbing for file in an unkown directory path only works first time in foreach loop? by toolic
in thread Globbing for file in an unkown directory path only works first time in foreach loop? by MarsRover

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