Frank after Michael...
>from mpe prompt enter sh

IFF the HPPXUDC.PUB.SYS is SETCATALOG-ed (like suggested in Inst Mnl)

Otherwise use [XEQ] SH.HPBIN.SYS -L or RUN SH.HPBIN.SYS;INFO="-L"
and consider adding the -c option if you want the shell to execute
a specific command.

And Michael before Frank...
>> access the file from the opsix shell -
>> tr -d "\00" < input file > output file

You should also be able to run most of the Posix utils, which live
in the HPBIN.SYS group (and have symbolic links in /bin directory)
from the CI prompt similar to...

 TR.HPBIN.SYS '-d "\00"' < inputFile > outputFile

Notice that I/O redirection of the CI (outside the 'info string')
will create the outputFile as a TEMP file by default (whereas Posix
does not know a beast like job/session temporary files).

Regards, Lars.