Internally, for forking, Bash stores the function definitions in environment variables. Variables with the content "() ….".

Something like the following works without "officially" declaring a function:

Code: [Sélectionner]

$ export testfn="() { echo test; }"
$ bash -c testfn
test
$
Just informational(2):

It is possible to set function names containing slashes:

Code: [Sélectionner]

/bin/ls() {
  echo LS FAKE
}