Dear mscharrer Thanks a lot for your help

I have taken into consideration what you have said. In fact the last line of my subroutine is:

chdir("$path_to_the_script_directory") or die;
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And I do not have any errors (when I do not use "or die" for process() )

But in my operations of process(), I have used :

while (my $line = <$INFILE>){
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And when I want to print $_ after the loop, I have :

Use of uninitialized value in concatenation (.) or string at
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