It may help to copy and paste your teacher's actual instructions. Items 1 & 2 aren't altogether clear, especially instructions of the form exit when the file is an empty file, and print the last line of the file - an empty file doesn't have a last line. Have you "reinterpreted" the actual instructions for us?

You don't show us the code you've tried that uses File::Find.

Did your teacher specify that you need to search "everywhere" for the file (that's a pretty big ask depending on how you choose to interpret "everywhere"). If not, just assume the current directory and ignore File::Find.

There are many quirks in your code. Here's a cleaned up version of your code followed by some comments on the changes.

#! /usr/bin/perl
# Assignment 9, check and read files and directories

use strict;
use warnings;
use Module1;

assnintro();

while (1) {
    print "Enter one file or directory name: ";
    my @params = split /\s+/, <>;

    if (@params != 1) {
        print color 'red';
        print "One directory or file entry expected.\n";
        print color 'reset';
        next;
    }

    my $input = $params[0];

    if (!-e $input) {
        print color 'red';
        print "The file or directory '$input' doesn't exist.\n";
        print color 'reset';
    } elsif (-d $input) {
        last if !doDir($input);
    } else {
        last if !doFile($input);
    }
}


sub doDir {
    my ($input) = @_;

    print "'$input' is a directory.\n";

    my @subDirs = glob $input;

    return if !@subDirs;

    #...
    return 1;
}


sub doFile {
    my ($input) = @_;
    print "'$input' is a file.\n";

    #...
    return 1;
}
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Of note:

• do {} until loops are unusual in Perl and don't work the same as while and for loops.
• my $count = @array; assigns the number of elements in @array to $count.
• $input = (); is at best redundant.
• Use my @parameter; inside the loop to make it clear that is where it is used.
• Don't use empty blocks in if statements. Simply omit the else block, or complement the test as appropriate.
• Don't use the parameter array @_ as a general purpose array. sub pamcheck does some very strange stuff and doesn't work the way you think it does.

Sure you can look into another directory with the -e and other file test operators:

$ perl -e '$search_file = "/usr/bin/perldoc"; print $search_file if -e
+ ($search_file);'
/usr/bin/perldoc

$ perl -e '$search_file = "/usr/bin/perldoc"; print "file size of $sea
+rch_file is ",  -s ($search_file), "\n";'
file size of /usr/bin/perldoc is 224
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Using the File::Find module is certainly a good option in general, but might not be what you are requested to do in an assignment. And it involves relatively advanced topics such as callbacks and subroutine references that are likely to be beyond what you have covered so far.

I guess you missed that well-written introduction into File::Find written by a Perl Monk. Most of your questions are answered in the code samples there.

And regarding the "Camel book" you mentioned... it's more like an presentation of Perl than a complete documentation. I like to read it when taking a bath. When at work, I'd suggest to instead read the more detailed Perl documentation.

No matter what you do, learn about taint mode and how and why to untaint user input, especially since you are going to be using it to look for file names. It is impossible to overemphasize the importance of doing so!

Trust me, you'll be glad you did when you get out in the real world. :)

use File::Slurp;

my @dir_contents = read_dir($argv[0]);

for my $entry(@dir_contents){
    if (-d $entry){
    print $entry is a directory";
    }
    elsif (-f $entry){
    print $entry is a file";
    }
    else {
    print "not a directory or file <.<";
    }
}
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