On Mon, 25 Mar 2019 at 14:03, Andreas Kusalananda Kähäri <andreas.kah...@abc.se> wrote: > > On Mon, Mar 25, 2019 at 11:19:08AM +0100, Christophe Lyon wrote: > > Hi, > > > > I think I've noticed a bit of explanation missing in the documentation > > about parameter expansion. > > > > bash supports :+ and + expansion, but 'man bash' describes the former only. > > This is also true for the similar expansions (:-, :=, :?) > > > > Some documentation is available at: > > http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_02 > > and > > https://www.tldp.org/LDP/abs/html/parameter-substitution.html > > > > Thanks, > > > > Christophe > > It is not omitted. The paragraph before the list of parameters > expansions in the manual reads > > When not performing substring expansion, using the forms documented > below (e.g., :-), bash tests for a parameter that is unset or null. > Omitting the colon results in a test only for a parameter that is > unset. >
Hmmm right, I managed to miss it, despite read that part of the doc several times. Sorry for the noise. > Regards, > > -- > Andreas Kusalananda Kähäri, > National Bioinformatics Infrastructure Sweden (NBIS), > Uppsala University, Sweden.
