/tmp>cat shebang.pl
#!/no/such/perl -w

use strict;
use warnings;

print 'Hello\n';
/tmp>chmod +x shebang.pl

/tmp>./shebang.pl
-bash: ./shebang.pl: /no/such/perl: bad interpreter: No such file or directory

/tmp>

##</code><code>##

/tmp>cat shebang.pl
#!/etc/passwd

use strict;
use warnings;

print 'Hello\n';pstree -al

/tmp>chmod +x shebang.pl

/tmp>./shebang.pl
-bash: ./shebang.pl: /etc/passwd: bad interpreter: Permission denied

/tmp>

##</code><code>##

/tmp>cat shebang.pl

#!/usr/bin/perl -w
# ^- note: Shebang on second line, first line is empty!

use strict;
use warnings;

print 'Hello\n';
/tmp>chmod +x shebang.pl

/tmp>./shebang.pl
./shebang.pl: line 5: use: command not found
./shebang.pl: line 6: use: command not found
./shebang.pl: line 8: print: command not found

/tmp>

##</code><code>##

/tmp>echo 'pstree -Aal' >> shebang.pl

/tmp>./shebang.pl
./shebang.pl: line 5: use: command not found
./shebang.pl: line 6: use: command not found
./shebang.pl: line 8: print: command not found
init
  .
  .
  .
  |-sshd
  |   `-sshd
  |       `-sshd
  |           `-bash
  |               `-bash
  |                   `-pstree -Aal
  .
  .
  .

##</code><code>##

/tmp>perl -e '$_=<STDIN>;print ord $_' < shebang.pl
10
/tmp>