mxhp version 1.38 was compiled under HPUX 9.01 and as you can see the
README file is under construction.  However, let me know if it works or
not when you grab it.  Get the file ~ftp/pub/mx/unix/bmx.tar to obtain
instructions on unix utilities such as bmx

To install:

uncompress mxhp.Z
chmod +x mxhp
mv mxhp mx
mv mx /usr/local/bin (wherever you keep such binaries; do this as root)

To execute:

mx < inputfile.mx > outputfile.mx &

See the directory ~ftp/pub/mx/examples for example files.