Question

I am trying to perform some modification on a typical g++ command line. I am trying to construct a regex looking for -o object_filename.o constructs. In order to test my matching pattern, I launch it in sed with an empty string as a substitution. But it does not work as expected since it removes nothing…

$echo "-o toto.o" | sed 's/-o [^ ]+//'
-o toto.o


Answer 1

You are missing a -E flag; without it, + is not treated as a regex meta-character:

$echo "-o toto.o" | sed -E 's/-o [^ ]+//'

The above produces an empty output, as expected.