On Windows APE doesn't need to modify itself because it's an MZ executable. On UNIX the MZ is the prologue to a shell script, which calls printf 'ELF HEADER' >$

On Windows APE doesn't need to modify itself because it's an MZ executable. On UNIX the MZ is the prologue to a shell script, which calls printf 'ELF HEADER' >$0; exec $0 to make it conform to the local convention. For subsequent executions it won't need to self-modify so you can simply prime the ape binary once before copying it to /usr/bin if you're an admin. Think of it like a zero-step install wizard that takes a few microseconds.