"You're not thinking fourth dimensionally" -- Doc Brown
"Please excuse the crudity of this model as I didn't have time to build it to scale or paint it." -- Doc Brown
Mcfly is for working with multiple Concourse instances that may be at different versions. Mcfly will determine the version of Concourse on the ATC, and use the corresponding version of fly. If you don't have that version, it will download it.
mcfly works for all fly commands that have a valid -t <target> argument.
Depends on yq and curl.
Recommended installation is to symlink fly to mcfly in your PATH.
ln -sf ../workspace/mcfly/mcfly ~/bin/fly