Debugging GNU make

Question

Is there a command line way in make to find out which of the prerequisites of a target is not updated?

Answer 1

Your question is a little unclear. If you want to see which prerequisite files have not been modified recently, use ls -l to see their modification time. If you want to see what make is doing, try this:

# Make will announce when it is making this target, and why.
sometarget: preq1 preq2 preq3
    @echo making $@
    @echo The following preqs are newer than the target: $?
    do_things