rakhi@rakhi-Inspiron-3542:~/mozilla-central$ ls mach
mach
rakhi@rakhi-Inspiron-3542:~/mozilla-central$ ./mach build
 0:03.87 /usr/bin/make -f client.mk -s
 0:04.79
 0:04.80 The CLOBBER file has been updated, indicating that an incremental
 0:04.80 build since your last build will probably not work. A full/clobber
 0:04.80 build is required.
 0:04.80
 0:04.80 The reason for the clobber is:
 0:04.80
 0:04.80  Bug 1253431 - Testing to see if a clobber fixes OSX debug build issues
 0:04.80
 0:04.80 Clobbering can be performed automatically. However, we didn't
 0:04.80 automatically clobber this time because:
 0:04.80
 0:04.80   Automatic clobbering is not enabled
 0:04.80   (add "mk_add_options AUTOCLOBBER=1" to your mozconfig).
 0:04.80
 0:04.80 The easiest and fastest way to clobber is to run:
 0:04.80
 0:04.80  $ mach clobber
 0:04.80
 0:04.80 If you know this clobber doesn't apply to you or you're feeling lucky
 0:04.80 -- Well, are ya? -- you can ignore this clobber requirement by
 0:04.80 running:
 0:04.80
 0:04.80  $ touch /home/rakhi/mozilla-central/obj-x86_64-unknown-linux-gnu/CLOBBER
 0:04.80
 0:04.80 make: *** [/home/rakhi/mozilla-central/obj-x86_64-unknown-linux-gnu/CLOBBER] Error 1
 0:04.84 40 compiler warnings present.
rakhi@rakhi-Inspiron-3542:~/mozilla-central$