It quite plainly tells you that the
-c option does not exist.
On HP-UX, you might be able to find a different version of mailx by enabling the UCB and/or XPG4 subsystems. I can't tell whether those would have a
-c option either, though.
If you have śendmail (not necessarily Sendmail, just a command implementing the Sendmail API -- I believe at least both Exim and Postfix offer a /usr/lib/sendmail or /usr/sbin/sendmail command) you can pipe directly to that.
Code:
cat <<HERE /usr/uc4/tmp/PENDINGSD.txt | sendmail -oi -t
Subject: BDC reminder
From: sender@email.com
To: receiver@email.com
Cc: EMAIL_IDS_CC#
HERE
