Define a command on xelatex command line

I would like to define the command qonly on the xelatex command line to be the string chapter07. Later in my LaTeX file I will have an ifdef that will provide the argument to an includeonly if qonly is defined.

This works if I am using latexmk:

$ latexmk -usepretex='defqonly{chapter07}' -pdfxe book.tex -bibtex

But this does not work with xelatex:

$ xelatex 'relaxdefqonly{chapter07}' book.tex

It gives me this error:

xelatex 'defqonly{chapter07}' book.tex
This is XeTeX, Version 3.14159265-2.6-0.999992 (TeX Live 2020) (preloaded format=xelatex)
 restricted write18 enabled.
entering extended mode
LaTeX2e <2020-02-02> patch level 5
L3 programming layer <2020-03-06>

! LaTeX Error: Missing begin{document}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...

<*> defqonly{chapter07} b
                           ook.tex
? ^D
! Emergency stop.
 ...

<*> defqonly{chapter07} b
                           ook.tex
No pages of output.
Transcript written on texput.log.
$ 

Is there any way do this?

EDIT: One of the posters was confused why I have the backquotes above. The reason is that I’m using MacOS and my shell is zsh, which interprets the backquotes as a quote mark, so it’s necessary to quote it. Here’s what happens if I don’t provide the backquote:

% xelatex defqonly{chapter07} book.tex
This is XeTeX, Version 3.14159265-2.6-0.999992 (TeX Live 2020) (preloaded format=xelatex)
 restricted write18 enabled.
entering extended mode
! I can't find file `defqonly{chapter07}'.
<*> defqonly{chapter07}
                        book.tex
(Press Enter to retry, or Control-D to exit)
Please type another input file name:

xelatex defqonly{chapter07} input{book}