Capturing the output of a failed command in helix

Some commands will set its exit code to a non-zero even when there are some output we need. One of them is typos, a spell checker written in Rust, which make sense since the existence of the typos is the failure state.

The problem occurs when I want to also use its output in helix. When I use :append-output typos (:insert-output is also available), the command will just fail saying that the typos command exit with code 2.

A quick way to force to read the output is to pipe the output of typos into tee. tee can write to a target file and standard output at the same time. Unless pipefail is set, the shell will also consider the whole command to be a success.

So the final command is

:append-output typos | tee

For this particular problem of checking the typos in the file, however, I should just use the LSP server for typos.