zsh: Is it possible to trace all functions and commands called and aliases expanded during a command’s execution?

Question

I want something like this:

# source:
a() b mp3 m4a "$@"
b() eval "${1}-to-${2} $@:q"
alias mp3-to-m4a='ffmpeg ...'
# 
$ traceall a a.mp3 a.m4a
 # should return:
 Functions:
 a
 b
 Aliases:
 mp3-to-m4a
 commands:
 ffmpeg

Answer 1

You might look at trap with the DEBUG pseudosignal. This only triggers for commands and functions, though, and only after alias expansion. You want to read the details in the zsh manual, because it runs a command or function giving it information about what's about to be executed, rather than recording information directly; you could use this hypothetically to implement a full debugger.

Answer 2

Turn xtrace globally:

> set -x; a a.mp3 a.m4 ; set +x

or turn on xtrace for functions, then execute it:

> typeset -tf a   # turns on xtrace for function a and below
> a a.mp3 a.m4

> typeset -Tf a   # turns on xtrace for function a only
> a a.mp3 a.m4