my-env/gen-makefile.sh

#!/bin/bash
mv Makefile Makefile.bak
echo -e "# Autogenerated at $(date +'%d.%m.%Y %H:%M') using ${BASH_SOURCE[0]}\n" > Makefile

for file in ./packs/*; do
    cat ${file} >> Makefile
    echo >> Makefile
done;

for file in ./install/*; do
    name=${file##*/}
    name=${name%.sh}
    desc=$(grep -m 1 -oP "(?<=^##makedesc:\s).*$" ${file})
    [ -z "$desc" ] && desc='<no description>'
    echo -e "##${name}: ${desc}\n${name}:\n\t${file}\n" >> Makefile
done;

cat << EOF >> Makefile
##help: Show this help message
help: Makefile
	@echo "Usage:"
	@echo "\tmake <goal>\n"
	@echo "Available goals:"
	@sed -n 's/^##//p' \$< | column -t -s ':' |  sed -e "s/^/\t/"

##<goal>_: Same as 'cat ./install/<goal>'
%_:
	@cat ./install/\$*
EOF

echo "New ./Makefile has been generated!"
echo "Old one has been saved as ./Makefile.bak"
echo
make help