I don't understand why you run two copies of Perl. What about just 
... | perl -pe 'BEGIN { $|=1; } s/\Qhide_me/removed/ig' | tee -a test.
+log

[download]

or 

... | censor_passwd | tee -a test.log

[download]
#!/usr/bin/perl

# censor_passwd

use warnings;
use strict;

my $password = "hide_me";

$| = 1;

while (<STDIN>) {
   s/\Q$password/removed/ig;
   print;
}

[download]

Update: By the way, this tool can be used to help guess the password. For example, feeding "abcdef" to this script checks the following passwords all at once:

In reply to Re: Filtering passwords from the output of a script by ikegami
in thread Filtering passwords from the output of a script by quester

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