getargv is a tool to get the arguments that were passed to another running process. It is intended to provide roughly the same functionality as /proc/<pid>/cmdline on linux. On macOS you only have ps -o args= <pid> available to you, which is space separated and therefore not guaranteed to parse the same way as when it was originally passed to the process, as arguments could have contained escaped or quoted spaces, or even empty arguments.
getargv can only see your processes by default, which is often sufficient. If you need to see the arguments of a process owned by another user, run sudo getargv <pid>.
ssh does not provide the remote command passed on the command line as a token in the ~/.ssh/config, getargs allows you to create a condition which checks if a remote command was specified on the cli, and if not provide a default command.ssh in using the git username, so there is normally no way for ssh to differentiate which account you are using. getargv allows you to check.Your system must support sysctl and KERN_PROCARGS2, which probably means macOS 10.3 or later, though I haven't tested older versions. You'll also need a non-ancient clang (c99 is required) or you'll have to override the compiler flags with CC, EXTRA_CPPFLAGS, and EXTRA_CFLAGS.
Clone the repo and run make.
I've built getargv on macOS 10.7-12.0, using only the CLT package, not the full Xcode install. If you need to override variables, do so after the make command, eg: make EXTRA_CPPFLAGS=-DMACRO EXTRA_CFLAGS=-std=c17. If you are trying to build on a version of macOS earlier than 10.7, let me know how it goes.
Run make install, installs to the /usr/local/ prefix by default, change with the PREFIX make variable.
Run make && make -C test.
I've tested getargv on macOS 10.7-12.0, and run CI against 10.15 & 11.0.