The command works in the Lua console:
redstone pulse left 3 0.1
to generate three 0.1 second long redstone signals to the left of the computer.
If I enter this into a program and then want to run it, it doesn't work. What else should I consider?
However, if I enter this into a program and then want to execute it, it does not work.
A program in ComputerCraft is interpreted and executed from Lua.
This "redstone pulse left 3 0.1" is not a Lua command, but an independent program.
You can call this external program with 'shell.run ("redstone pulse left 3 0.1")' via the Lua interpreter.
"No such program": /
Pay attention to spelling?
Yes. So at least now I understand the problem. The command does not work in the Lua console as I said in the question, but only on its own. And this shell.run should then be able to execute this program as if I had simply entered it instead of via Lua?
I guess I have to use shell.run in the Lua console too?
Exactly, as soon as you use the Lua interpreter, you have to use shell.run for programs that have already been written and pass the program name with parameters.
If you are only in the console you can call the programs directly without shell.run
Ok, I did it, thank you very much