Do you love M4, too??
http://www.cs.stir.ac.uk/~kjt/research/pdf/expl-m4.pdf
https://www.jpeek.com/articles/linuxmag/2005-02/
https://mbreen.com/m4.html
https://elly.town/d/blog/2022-01-05-m4.txt
>>6
MAWK or GAWK.
https://www.gnu.org/software/gawk/
https://linux.die.net/man/1/mawk