"Martin Schwenke" <[email protected]> wrote:
> Neither bash.info or bash(1) documents parameter expansion of the
> form:
>
> ${parameter+word}
It's documented, but it's easy to miss. Just before the list of
parameter expansion forms is this paragraph:
In each of the cases below, word is subject to tilde expansion,
parameter expansion, command substitution, and arithmetic
expansion. When not performing substring expansion, bash tests
for a parameter that is unset or null; omitting the colon
results in a test only for a parameter that is unset.
paul
