plankton@chum-bucket:~$ cat test.pl 
#!/usr/bin/perl -w

use strict;

my $var = 'hello world';

print "$var\n";
plankton@chum-bucket:~$ perl -c test.pl 
test.pl syntax OK
plankton@chum-bucket:~$ cat test2.pl 
#!/usr/bin/perl -w

use strict;

my $var = 'hello world';

print $var\n";
plankton@chum-bucket:~$ perl -c test2.pl 
Backslash found where operator expected at test2.pl line 7, near "$var\"
        (Missing operator before \?)
String found where operator expected at test2.pl line 7, at end of line
        (Missing semicolon on previous line?)
Can't find string terminator '"' anywhere before EOF at test2.pl line 7.