while true; do make all & sleep 1m; done Welcome to orphan land. (^C to see.) Don't do this folks. The 'make all' invocations may also potentially overlap and

while true; do make all & sleep 1m; done Welcome to orphan land. (^C to see.) Don't do this folks. The 'make all' invocations may also potentially overlap and corrupt your builds. To be fair, you fixed that issue here: while true; do make all & sleep 1m & wait; done But the orphan issue remains.