🚀 go-pugleaf

The length byte in command tails cannot be negative.  The command tail is
taken from the Pexec call and stored in the base page for a process.
The base page is 256 bytes; the last 128 bytes of the base page are used
to store the command tail, including the length byte.  Thus the maximum
length of a command tail is 127 bytes.

The commercial shells that allow passing command lines greater than 127
bytes (Mark Williams msh, Beckemeyers csh, etc.) pass the actual command
line using environment variables, with the first 127 characters of the
command line put into the command tail of the Pexec call for compatibility
reasons.

As of the latest releases from Beckemeyer and Mark Williams products they
have gotten together and agreed on common formats for using the environment
strings so that their products can be used in each others environments.

The environment strings that they expect look something like

"name=value\0name=value\0...name=value\0\0"

if I remember correctly.  It's documentated reasonably well in their manuals;
some of Beckemeyers products even come with the source to example getenv
and putenv functions.

dgc