makefile auto help

gistfile1.txt

 # Add the following 'help' target to your Makefile
 # And add help text after each target name starting with '\#\#'
 # A category can be added with @category

 HELP_FUN = \
         %help; \
         while(<>) { push @{$$help{$$2 // 'options'}}, [$$1, $$3] if /^(\w+)\s*:.*\#\#(?:@(\w+))?\s(.*)$$/ }; \
         print "usage: make [target]\n\n"; \
     for (keys %help) { \
         print "$$_:\n"; $$sep = " " x (20 - length $$_->[0]); \
         print "  $$_->[0]$$sep$$_->[1]\n" for @{$$help{$$_}}; \
         print "\n"; }     

 help:           ##@miscellaneous Show this help.
     @perl -e '$(HELP_FUN)' $(MAKEFILE_LIST)

 # Everything below is an example

 target00:       ##@foo This message will show up when typing 'make help'
     @echo does nothing

 target01:       ##@foo This message will also show up when typing 'make help'
     @echo does something

 # Remember that targets can have multiple entries (if your target specifications are very long, etc.)
 target02:       ## This message will show up too!!!
 target02: target00 target01
     @echo does even more
The output is this:

 $ make help
 usage: make [target]

 options:
   target02                    This message will show up too!!!

 foo:
   target00                    This message will show up when typing 'make help'
   target01                    This message will also show up when typing 'make help'

 miscellaneous:
   help                    Show this help.