Question

I read build/envsetup.sh in android source code, and found a command
time make $@
in function mm.
But I don’t know the meaning about it. Who can I help me?

Answer 1

The time command times the following command and outputs resource usage.

make is (usually) used for calculating dependencies and building source code.

So time make $@ runs a timer, while building whichever parameters were passed in ($@).

From your terminal, typing man -s 1 time and man -s 1 make will give you more information.