based on https://saintgimp.org/2013/01/22/merging-two-git-repositories-into-one-repository-without-losing-file-history/ but using --allow-unrelated-histories with newer git versions

combine-repos.sh

git init
touch initial.txt
git add initial.txt
git commit -m 'initial commit'
git remote add -f shorttxt [email protected]:hmheng/cpl_short_text_table.git
git merge shorttxt2/master --allow-unrelated-histories
git mv -k * ./shorttxt/

#investigate this because -k is not desirable
#shopt -s extglob
#git mv -n ./!(exclude_me|exclude_me) ./destination_folder


# a variation on this is documented here; https://medium.com/@filipenevola/how-to-migrate-to-mono-repository-without-losing-any-git-history-7a4d80aa7de2