Hello friends,
What has always bother me on ArduPilot development was the lack of completion on the tools we used.
Our command-line commands can be quite long and memorizing them when we aren’t using them every day could be a pain.
To reduce this pain and allow newcomers to have some more help, I have made some shell completion for waf and sim_vehicle.py.
For those that don’t know what it is, the completion system allows you type the start of a word or command and let the system complete it, by double press TAB key ! When you use a terminal that is a very convenient feature, plenty of software have some completion.
The completion scripts are now in master branch, but they should appear on 4.x series on each vehicle soon. Otherwise, I will make some documentation to put the scripts on the system to allow completion to work on each branch.
I made completion for two shell : Bash and Zsh. Most users should be on Bash, as it is the default shell on Debian like system (like Ubuntu).
on Bash
To install the completion, you should either, source the main script on your current terminal or source the main script on your bash configuration.
Direct use
From ArduPilot root directory, simply use :
source ./Tools/completion/completion.bash
And now completion works from your terminal instance. If you close the terminal, the completion feature is removed.
Permanent use
Edit you .bashrc file, it is on your Home directory but it is a hidden file (CTRL+H on Ubuntu to reveal them). Then put at the end of the file :
source PATH_TO_ARDUPILOT_DIRECTORY/Tools/completion/completion.bash
where PATH_TO_ARDUPILOT_DIRECTORY is the path to ArduPilot directory (simple 
)
Usage
You can now abuse of your TAB key on waf and sim_vehicle.py call ! See the video at the end.
On ZSH
Zsh don’t allow live loading of completion. So you have to source the completion script in your .zshrc file. Like for Bash, you will find it hiding on your home !
Put at the end of the file :
source PATH_TO_ARDUPILOT_DIRECTORY/Tools/completion/completion.zsh
where PATH_TO_ARDUPILOT_DIRECTORY is the path to ArduPilot directory (simple ). Notice the difference, the extension is .zsh !
Video
I have made a simple video to show usage of completion :
https://youtu.be/UpY7SZ6FXi8
Future improvements
I am not a command-line wizard so I tried my best to get a maintainable completion feature. Not all features are available yet, but most used one’s are implemented. If some magician knows how to make the completion faster/better, feel free to submit a PR !