I'm having trouble using the following code inside my Perl script, any advise is really appreciated, how to correct the syntax?

# If I execute in bash, it's working just fine

bash$ whois google.com | egrep "\w+([._-]\w)*@\w+([._-]\w)*\.\w{2,4}" |awk ' {for (i=1;i<=NF;i++) {if ( $i ~ /[[:alpha:]]@[[:alpha:]]/ )  { print $i}}}'|head -n1

[email protected]

#-----------------------------------

#but this doesn't work 

bash$ ./email.pl google.com
awk:  {for (i=1;i<=NF;i++) {if (  ~ /[[:alpha:]]@[[:alpha:]]/ )  { print }}}
awk:                              ^ syntax error

# Here is my script
bash$ cat email.pl 
####\#!/usr/bin/perl         


$input = lc shift @ARGV;

$host = $input;

my $email = `whois $host | egrep "\w+([._-]\w)*@\w+([._-]\w)*\.\w{2,4}" |awk ' {for (i=1;i<=NF;i++) {if ( $i ~ /[[:alpha:]]@[[:alpha:]]/ )  { print $i}}}'|head -1`;
print my $email;

bash$