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I don't know PDP7 assembly either, but I don't see how it could stand for "previous directory" (and be equivalent to today's `cd -`). Any command to change dire

I don't know PDP7 assembly either, but I don't see how it could stand for "previous directory" (and be equivalent to today's `cd -`). Any command to change directory needs to be done in-process by the shell, so it would need to be implemented as a builtin, not a standalone executable. So "print directory" or (print something about the) "parent directory" seem more likely to me.

kragen 7y ago
In the earliest versions of Unix, the shell didn't fork to run programs. It would exec the program, and then the program would exec the shell instead of exiting. Makes sense, right? That's what you'd do if you didn't have an operating system at all, and it's how, for example, CP/M worked. So you could write "cd" as a non-built-in command. But it sounds like the other commenters have figured out that it's "pack directory".
- deleted 7y ago
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