On 19Mar2009 12:19, Daniel B. Thurman dant@cdkkt.com wrote:
OK, I found out why I had a problem!
I setup an intentional sed error: $ (re="-e ''s/b/h/'"; echo "boo" | sed $re | echo "done"; echo ${PIPESTATUS}) done sed: -e expression #1, char 1: unknown command: `'' 0
[ I'm sure you know everything I say below based on previous posts, but it seems worth saying purely for other readers... ]
Ok, but I strongly recommend you never us a regexp unquoted - the necessary backslash nesting gets nasty real fast. A better way is like this:
re='s/b/h/' sed -e "$re"
or for complex stuff, write a file called "sedf" (for example) containing a full sed script:
s/b/h/ /foo/d /bah/b again
etc. Then:
sed -f sedf
The point here, unrelated to the pipe exit status issue, is to keep the sed stuff easy to write and undamaged by shell substitution.
On the pipe stuff, another approach (less convenient than PIPESTATUS), is a flag approach like you original attempt, but using files:
badness=/tmp/foo$$bad { x || touch $badness; } \ | { y || touch $badness; } \ | { z || touch $badness; } if [ -f $badness ] then rm $badness echo badness happened >&2 fi
It has the advantage of working in non-pipe circumstances (nested subshells, etc).
Cheers,