This is a faq: see How do I compute the difference of two arrays? How do I compute the intersection of two arrays? in perlfaq4.

Assuming no special characters in your inputs, you could repair your code by using the special variable $" - it controls how arrays are interpolated into strings. Something like:

@array = <FILE>;
@pattern = <FILE2>;
local $" = '|';
foreach $line(@array) {
    if ($line =~ m/@pattern/) {
        print $line;
    }
}
[download]

| functions as an or in regular expressions; see Metacharacters in perlre. If your input may contain regular expression metacharacters, you can use \Q and \E with a map to escape those and accomplish the same thing (see Quote and Quote like Operators in perlop):

@array = <FILE>;
@pattern = map "\Q$_\E", <FILE2>;
local $" = '|';
foreach $line(@array) {
    if ($line =~ m/@pattern/) {
        print $line;
    }
}
[download]

Finally, please wrap code in <code> tags to preserve formatting and make downloading code easier for monk who wish to help; see Writeup Formatting Tips.

You want to check all patterns against all lines. That's two loops.

1. For every pattern,
   1. For every line,
      1. If the line matches the pattern,
         1. Print the line.

To avoid printing the same line more than once, you could join the patterns into one. That moves one of the loops into the regex engine.

1. my $pattern = join '|', @patterns;
2. For every line,
   1. If the line matches the combined pattern,
      1. Print the line.

        foreach $line (@array) {
                foreach $pat (@pattern) {
                        if($line =~ /$pat/) {
                                push (@new_array, $line);
[download]

Did you try the code posted in Re: comparing two arrays and displaying scalar matches? Would you care to explain why TEST FAILED ABORT | 24 does not match the pattern TEST? Why are you not wrapping code in <code> tags?

TEST FAILED ABORT | 24 also contains the pattern TEST.

Why shouldn't TEST FAILED ABORT | 24 be in the output as well?

CountZero

A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

$size = @array;
$size2 = @pattern;

foreach $line(@array)
{
if (@array[0 .. $size] =~ @pattern[0 .. $size2])
{

print $line;
}
}
[download]

What background do you have in programming? I mean this with respect - it seems like you are currently trying to tackle a problem which is beyond your current understanding. For example,
• You assign $line as an iterator, but then you never use the value. See Foreach Loops.
• =~ (Binding Operators) is a scalar operator, but you are feeding it two array Slices.
• The upper index you are using on your array slices is larger than the biggest index in the array.

We are glad to help neophytes learn the language, and will do our best to guide your development. I would strongly suggest you either take a course or get a good reference book, such as Programming Perl, Third Edition.

While some significant optimizations have been suggested above, the simplest code which seems to conform to what you expect might look something like:

foreach $line (@array) {
    foreach $pat (@pattern) {
        if ($line =~ m/$pat/) {
            print $line;
        }
    }
}
[download]

This might not behave as you expect, depending on what is in your @patterns array - see perlretut for some introductory material on regular expressions.

@array = <FILE>;<br>
@pattern = <FILE2>;<br>
foreach $line(@array)<br>
{<br>
if ($line =~ m/@pattern/)<br>
}<br>
print $line;<br>
}<br>
}
[download]

Ideas:
1. use strict; use warnings; would have told you that the curly at line 6 faces the wrong way (is a close_curly, not the open required in an if... clause.
    
2. Proofread, test anything you plan to post here with perl -c scriptname.
    
3. Review the use of <c>...</c> (or <code>...</code>) tags at Markup in the Monastery. The HTML break tags don't belong inside code tags unless your code actually has <br> tags.