Hi @Anthony ,
When you use SHCall, it's translated into a remote SSH command that includes all arguments inline on the shell. Basically something like ssh user@host bash -c '...'
However, there is an OS-enforced limit on how long this can be, which is typically between ~32K and ~64K characters. It looks like you're there exactly, and you may be able to see this limit with getconf ARG_MAX. Note that you would also get this error if you did ssh user@host bash -c 'echo "Really long....."'.
So bottom line -- this is an OS/SSH limit. To work-around it, you can just write out $arg to a file, and have your script read in that file.
Thanks,
Alana