Further I was, because the upper listed string wasn't expected for this
code (until it occured the first time ;-) )

Normally there has been only one occurence of "(file) (.., line)" or
"(.., line) (file)" per string, so the regex did quite do what I
expected - never the less you are right - instead of the '*' operator I
should have used a '?' operator for the repetition.

So far many thanks for your recommendations - but the question is if it
is ok that a regex may block a process such a long time?