ref man iwd.network:
> Key-value lines contain a setting key, an equal sign and the value of
> the setting. Whitespace preceding the key, the equal sign or the value,
> is ignored. The key must be a continuous string of alphanumeric and
> underscore characters and minus signs only. The value starts at the
> first non-whitespace character after the first equal sign on the line
> and ends at the end of the line and must be correctly UTF-8-encoded.
> […]
> String values, including file
> paths and hexstrings, are written as is except for five characters that
> may be backslash-escaped: space, \t, \r, \n and backslash itself.
> The latter three must be escaped. A space character must be escaped if
> it is the first character in the value string and is written as \s.
I guess this is what is expected then:
```
$ echo -e " \t \r \\ "
\
$ echo -e " \t \r \\ " | sed "s=\\\=\\\\\\\=g;s=\t=\\\t=g;s=\r=\\\r=g;s=^ =\\\s="
\s \t \r \\
```
