It sounds like you're trying to run the cp or copy commands from the perl script directly, much as you would do in shell script. You can't really do that - if you want to run a system command (such as cp), you'd need to invoke perl's system() function - e.g.:

system("cp file1 file2");
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If you want to copy files in an operating system-independent way (and you probably do), then I'd like to direct you to the File::Copy module, which comes with Perl as standard. Use it thusly: (ripped verbatim out the POD)

use File::Copy;
copy("file1","file2");
copy("Copy.pm",\*STDOUT);'
move("/dev1/fileA","/dev2/fileB");
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use strict;
use warnings;
my @shell_rtn_val;

print "Enter name of file to copy: ";
my $file = <STDIN>;  # open STDIN and get input
chomp $file;  # remove the \n
$file =~s /\\/\\\\/g;  # Convert to Win32 Shell path sep
$file =~s /\//\\\\/g;  # Use Unix path's too :-)
@shell_rtn_val = `copy $file $file."bak"`;
foreach(@shell_rtn_val){
  #Let's look for interesting stuff and process it
  # $_ is implicitly searched for in each if
  # just like you wrote: $_ =~ m/regex-pattern/
     if ( /(\d) file\(s\) copied/ ){ 
    my $num = $1;print "You copied $num files";
    }
     if ( /cannot find/ ){ 
    print "System can't find a file by that name";
    }
    if ( /syntax/ ){ 
    print "Bad syntax";
    `copy /?`;
    }
}
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Perhaps if you gave an example of what you tried (but didn't work) we could help you.

CountZero

"If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law