Install an additional completion function for bash

Question

I have never used bash completion of todo.txt cli; however, I have decided to give it try. On the author's github, it says:

(Optional, since v 2.9:) Install the Bash completion, either system-wide, for all users:

      $ sudo cp todo_completion /etc/bash_completion.d/todo
or 

      put it somewhere in your home directory and source it from your .bashrc:

Now in the install documentation for bash completion, it says:

The easiest way to install this software is to use a package; it is available
in many operating system distributions.  The package's name is usually
bash-completion.  Depending on the package, you may still need to source it
from either /etc/bashrc or ~/.bashrc (or any other file sourcing those). You
can do this by simply using:

# Use bash-completion, if available
[[ $PS1 && -f /usr/share/bash-completion/bash_completion ]] && \
    . /usr/share/bash-completion/bash_completion

So from my understanding, which may wrong, I should put

# Use bash-completion, if available
    [[ $PS1 && -f /usr/share/bash-completion/bash_completion ]] && \
        . /usr/share/bash-completion/bash_completion

in my ~/.bashrc. Now should I put todo-completion in /usr/share/bash-completion/bash-completion? If so, I only have /usr/share/bash-completion but there is a completion one level below bash-completion.

To be honest, I could be all wrong with this thought process. I have been doing numerous searches on todo and bash-completion but nothing has been too promising. So if this is all incorrect, how do I set up both up together?

Answer 1

If you add the file to /usr/share/bash-completion/ it will be overwritten by pacman when the package is next updated.

To prevent this from happening, use ~/.bash_completion, which is sourced at the end of the main completion script. From the FAQ:

Q. How can I insert my own local completions without having to reinsert them every time you issue a new release?

A. Put them in ~/.bash_completion, which is parsed at the end of the main completion script. See also the next question.

Alternatively, for system-wide access on Arch, you can place the file in /etc/bash_completion.d/.