harptabber and harptabber-gui
A tool for transposing harmonica tabs into different positions and tunings
Available as a CLI app, native GUI version and web app. Includes a visual "tab keyboard" for quick tab input.
Try the web app and download binaries at https://seebass22.itch.io/harmonica-tab-transposer
CLI version
$ harptabber --from 2 --to 1 tabs.txt
1 2 -2'' -2' -2 -2
-2 -2' 2
-2 -2' -2'' 2 -2' 1