use String::ShellQuote qw( shell_quote );

sub perl_quote { qq{"\Q$_[0]\E"} }
 
my $email_lit = perl_quote( $email );

my @cmd = (
   "perl",
   "-MDigest::SHA=sha256_hex",
   "-e", "print sha256_hex( $email_lit )",
   $email,
);

my $cmd = shell_quote( @cmd );

my $email_SHA256 = qx($cmd);
die "Can't spawn child: $!\n" if $? == -1;
die "Child killed by signal ".( $? & 0x7F )."\n" ) if $? & 0x7F;
die "Child exited with error ".( $? >> 8 )."\n" ) if $? >> 8;