Hi, I am using gnu make and in a Makefile I have, I see below rule. I want to add a similar rule with a recipe, but when I add a rule and its receipe on the next line by giving a tab or space for the recipe, I get make error.

dummy :
    @echo $(OBJS)

When i turned on the vim command :set list , i see:

dummy :$
^I@echo $(OBJS)$

What exactly are the characters before the recipe line(second line) which indent it from the start of line?

How do I enter them using keyboard (without having to copy paste the exisitng rule and then modifying it?

Where would I find information for various spaces/indents to be used in creating a Makefile from beginning, by hand(Not a automake/or other tool created makefile)?

thanks,

-AD.