* Eric Blake wrote on Sat, Jun 23, 2007 at 11:31:12PM CEST: > According to Bruno Haible on 6/23/2007 1:09 PM: > > But then use IFS (so that PATH elements containing spaces are handled > > correctly), ignoring empty fields from the cases C and D. In summary, > > something like this: > > > > pathx=`echo ":$PATH:" | sed -e 's/:::*/:.:/g' -e 's/^://' -e 's/:\$//'` > > Or, to avoid the sed when possible, you could do > > case `echo ":$PATH:" in
Why is there a need to fork here? case :$PATH: in > *::*) pathx=`echo ":$PATH:" \ > | sed -e 's/:::*/:.:/g' -e 's/^://' -e 's/:\$//'` ;; > esac I assume that using either/both of `which' or `type' are so non-portable or unparseable that it is out of the question (for Autoconf). Is that the case? I'm asking because in typical configure scripts, _AS_PATH_WALK is expanded rather often, its use of $PATH_SEPARATOR makes the above even longer, and if we have to fork anyway, and take care of `echo' issues here, it may make sense to look for a decent path finder algorithm in a preparation step. >>> I think SUSv3 wording is saying that pdksh is right and bash is wrong. :-/ >> >>I cannot find any specification of it at all in POSIX: The relevant text at [...] >> The shell shall treat each character of the IFS as a delimiter and use the >> delimiters to split ... into fields. >> >> Each occurrence in the input of ':' ... shall delimit a field ..." >> >>It is not clear whether empty fields can occur at all, and under which >>conditions they appear at the front or at the end of the result. To me this sounds pretty unambiguous: each ':' delimits a field, otherwise they would have written "any sequence of ..." as they did with IFS white space. That should certainly rule out result A. Result C is inconsistent wrt. interpretation at the beginning and the end of the input. And since I don't see where fields are to be nonempty, I don't see how result B is what is meant by the standard. Of course an explicit example would have been helpful. Cheers, Ralf
