1# $NetBSD: varname-dollar.mk,v 1.3 2020/08/19 05:40:06 rillig Exp $ 2# 3# Tests for the expression "$$", which looks as if it referred to a variable, 4# but simply expands to a single '$' sign. 5# 6# If there really were a special variable named '$', the expressions ${${DOLLAR}} 7# and $$ would always expand to the same value. 8 9# Using the dollar sign in variable names is tricky and not recommended. 10# To see that using this variable indeed affects the variable '$', run the 11# test individually with the -dv option. 12DOLLAR= $$ 13 14# At this point, the variable '$' is not defined. Therefore the second line 15# returns an empty string. 16.info dollar is $$. 17.info dollar in braces is ${${DOLLAR}}. 18 19# Now overwrite the '$' variable to see whether '$$' really expands to that 20# variable, or whether '$$' is handled by the parser. 21${DOLLAR}= dollar 22 23# At this point, the variable '$' is defined, therefore its value is printed 24# in the second .info directive. 25.info dollar is $$. 26.info dollar in braces is ${${DOLLAR}}. 27 28all: 29 @:; 30