This is the command I entered in the terminal while following "Ruby on Rails development with Mac OS X Mountain Lion", and its result:
rbenv install 2.0.0-p247
Downloading openssl-1.0.1e.tar.gz...
-> https://www.openssl.org/source/openssl-1.0.1e.tar.gz
Installing openssl-1.0.1e...
BUILD FAILED
Inspect or clean up the working tree at /var/folders/x8/19f_wwjx4gd26z6qdq874tj40000gs/T/ruby-build.20130919211135.42003
Results logged to /var/folders/x8/19f_wwjx4gd26z6qdq874tj40000gs/T/ruby- build.20130919211135.42003.log
Last 10 log lines:
RANLIB =true
ARFLAGS =
PERL =/usr/bin/perl
SIXTY_FOUR_BIT_LONG mode
DES_UNROLL used
DES_INT used
RC4 uses uchar
RC4_CHUNK is unsigned long
sh: make: command not found
/usr/local/bin/ruby-build: line 387: make: command not found
Please help!
/usr/local/bin/ruby-build: line 387: make: command not found
means rbenv can't compile Ruby because the necessary tools aren't available.