A program (binary, or executable) is a file on disk somewhere, in a recognized format. Common formats include ELF on Linux, ...

As an example, here’s [calebccf] with an emulated 6502 system in a busybox ash shell script. What’s in the emulator? A simple 6502 system with RAM, ROM, and an emulated serial port on STDIO.

Last month, we looked at signals, the rudimentary mechanism that processes on a Linux box can use to communicate events and state changes. We talked about how each of the signals can be sent manually ...

then # it's uppercase fi This is a classic shell-script trick: to ascertain if a character is a member of a class, replace it with null, then test to see if the resultant string is null (the -Z test).