This allows multi-call binaries to be easily invoked with a different
name. After installation, the name is set by creating a symlink. But in
build directories, we don't create the symlinks. (There are also other
ways to achieve the same thing, e.g. zsh supports $ARGV0, and exec -a
can be used, but those are either non-portable or are more complicated
to use.) The primary use-case for me is to test --help output for
multicall binaries.
Also reorder the help for env vars to group the more generic ones near
the top.
This was initially proposed in https://github.com/systemd/systemd/pull/24054,
but there were some comments about the implementation. I had a branch
with the patch, but I don't think I ever actually submitted it as a
pull request.
Let's introduce some helpers for generating uniform --help texts with
some minimal ANSI styling.
This shortens the help() functions generally, and allows us to change
the style at a single, central place.
This mostly just follows our current styling for --help, but it makes
two updates to it:
1. The command line summary at the very top of the --help text is now
prefixes with a grey ">" character to indicate it's a command line.
2. The human language introductionary description/abstract right after
that command line is set in italics, to emphasize it's not dry,
technical, structural information, but more human friendly prose.
Zbigniew Jędrzejewski-Szmek
Lennart Poettering