gf
$ gf
๐Ÿ“‹ Copied README-first bundle from repo root
$ gf docs
๐Ÿ“‹ Preset docs โ†’ clipboard
$ gf ~/project/app
๐Ÿ“‹ Gathered 12 files (1.2k chars) in 0.3s
# README promoted, duplicates removed, stats logged
curl -LsSf https://gf.bfoos.net/install.sh | bash

or:
cargo install --git https://github.com/BrianSigafoos/gather-files