检查Makefile中的tab

转：http://stackoverflow.com/questions/16931770/makefile4-missing-separator-stop

makefile has a very stupid relation with tabs , all actions of every rule are identified by tabs ...... and No 4 spaces dont make a tab , only a tab makes a tab...

o check i use the command

cat -e -t -v  makefile_name

it shows the presence of tabs with ^I and line endings with $ both are vital to ensure that dependencies end properly and tabs mark the action for the rules so that they are easily identifiable to the make utility.....

example :

Kaizen ~/so_test $ cat -e -t -v  mk.t
all:ll$      ## here the $ is end of line ...
$
ll:ll.c   $
^Igcc  -c  -Wall -Werror - c.c ll.c  -o  ll  $@  $<$
## the ^I above means a tab was there before the action part, so this lines ok .
 $
clean :$
   \rm -fr ll$
## see here there is no ^I which means , tab is not present ....
## in this case you need to open the file again and edit/ensure a tab
## starts the action part