Re: [EXPAND] Nested parameter expansion results in an empty string when quoted

[Todor Vlaev <t.vlaev@xxxxxxxxx>]

> The double-quotes here are unnecessary and should be left out for
> optimal compatibility. Note that this may require a temporary variable
> if the expansion is in a context where word splitting is performed.
> However, you are right that the double-quotes are permitted per POSIX.
>
> On the other hand, some double-quotes that are really necessary are
> missing:
>
> my_str=swan; last_char=${my_str#"${my_str%?}"}; echo "${last_char}"
>
> The inner double-quotes force any wildcard characters in $my_str to be
> taken literally. This is required to work correctly with the string
> sw*n, for example.
>
> It also happens to work around dash's bugs, both the above version and a
> version with the redundant quotes you like:
>
> my_str=swan; last_char="${my_str#"${my_str%?}"}"; echo "${last_char}"

Thanks for the useful tips!

> Fixing this requires a test suite. Without a test suite, any attempt to
> fix something is likely to break something else.

A bit worrying not to have regression tests, indeed.

In any case, there are plenty of workarounds to this minor issue, even
if not fixed there is a reference now for someone else who might
wonder.

Br,
Todor
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