my $string = join( "\n", qw(howdy partner goodbye Friend saynora adios Amigo) );
open(MY_FILE, '>my_file.txt');
print MY_FILE $string;
close(MY_FILE);
&edit_file('my_file.txt');

sub edit_file {
    my $my_file = shift;
    my $editor = $ENV{'editor'};
    system('vim', $my_file);
    my $validate = &validate_file($my_file);
    print "File is ok\n" if $validate;
}

sub validate_file {
    my $my_file = shift;
    open( MY_FILE, $my_file ) or die "Unable to open file\n";
    while( <MY_FILE> ) { 
        chomp( $_ );
        unless( $_ =~ /^[a-z]/ ) { 
            close( MY_FILE );
            print "Error at line $.\n";
            print "$_ does not begin with a lower case letter\n";
            print "Hit return to continue: ";
            <STDIN>;
            &edit_file( $my_file );
        }   
    }   
    close( MY_FILE );
    return 1;
}