#!/usr/bin/perl
my $input = join '', <STDIN>;
unlink 'sendmail.log'
  if -f 'sendmail.log';
open my $fh, '>sendmail.log'
  or die 'Cannot write to sendmail.log';
print $fh "CLI args: @ARGV\n";
if ( defined $input && length $input ) {
  print $fh "Executed with input on STDIN\n$input";
}
else {
  print $fh "Executed with no input on STDIN\n";
}