Stupid mailx question

Hi all

I am trying to port some scripts that were writen in tru64 over to linux
and when I try to execute the script that uses mailx to send a uuencoded
attachment that takes in a command as standard input from a file and
appends the standard output from the commands executed in that file and
then mail it to a number of users. 

On the alpha the commands work as you would expect however on the linux
box the standard imput from the file is passed to mailx as a litteral
with the mail message being the contents of the input file.


eg mailx -s "why does this work on an alpha" [email protected] < input-file


the input file contains the following:

on the alpha 
~<! /usr/bin/uuencode /usr/opt/sis/flx_interfaces/pay_alloc_report
PALLOX.xls

on the linux box* 
~! /usr/bin/uuencode /usr/opt/sis/flx_interfaces/pay_alloc_report
PALLOX.xls

* the linux version of mail/mailx does not appear to like ~<! command to
run a script or command but yet it is listed in the man page.

Is there something different with the RHEL implementation of mailx
(which is a posix implementation of mail) or am I doing something wrong
or stupid here.