I can easily make a pull request to make it and the other programs use shell.getRunningProgram, I'm just wondering if it's worth it

Useful information to include:

• Minecraft version: whatever master branch builds
• CC: Tweaked version: commit 17b7727 on master branch
• Detailed reproduction steps: on any computer run the command delete with no args, note that the printed usage is rm <paths> not delete <paths>

This is also true for copy, move and rs. Honestly, I don't mind - if you want to put a PR together, I'll merge it, but it's not a bug I'm especially worried about :p.

Also worth noting that the "correct" thing to do is arg[0]¹, rather than shell.getRunningProgram(). The former returns the actual command entered, the latter just the path.

[1]: Some terrible shells, such as mbs, don't correctly provide arg, which makes things much worse!