I wrote this one
#!/bin/bash
if [ "$#" -eq "0" ]; then
set -- bash
fi
docker start termux-docker >/dev/null 2>&1 || \
docker run --detach --init --name termux-docker -it termux/termux-docker:latest
docker exec -itu system termux-docker "$@"
Using this I can invoke termux commands from my regular shell like this.
termux apt-file search xcb-image.pc
Or simply enter termux environment with termux command.