Rconfig sample

rbconfig.json

{ 
   "CHDIR"   =>"cd -P",
   "RMALL"   =>"rm -fr",
   "RMDIRS"   =>"rmdir --ignore-fail-on-non-empty -p",
   "RMDIR"   =>"rmdir --ignore-fail-on-non-empty",
   "CP"   =>"cp",
   "RM"   =>"rm -f",
   "PKG_CONFIG"   =>"pkg-config",
   "DOXYGEN"   =>"",
   "DOT"   =>"",
   "MAKEDIRS"   =>"/bin/mkdir -p",
   "MKDIR_P"   =>"/bin/mkdir -p",
   "INSTALL_DATA"   =>"/usr/bin/install -c -m 644",
   "INSTALL_SCRIPT"   =>"/usr/bin/install -c",
   "INSTALL_PROGRAM"   =>"/usr/bin/install -c",
   "SET_MAKE"   =>"",
   "LN_S"   =>"ln -s",
   "NM"   =>"nm",
   "DLLWRAP"   =>"",
   "WINDRES"   =>"",
   "OBJCOPY"   =>":", "   OBJDUMP"=>"objdump",
   "ASFLAGS"   =>"",
   "AS"   =>"as",
   "AR"   =>"ar",
   "RANLIB"   =>"ranlib",
   "try_header"   =>"",
   "COUTFLAG"   =>"-o ",
   "OUTFLAG"   =>"-o ",
   "CPPOUTFILE"   =>"-o conftest.i",
   "GNU_LD"   =>"yes",
   "GCC"   =>"yes",
   "EGREP"   =>"/bin/grep -E",
   "GREP"   =>"/bin/grep",
   "CPP"   =>"gcc -E",
   "CXXFLAGS"   =>" -O3 -ggdb -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Werror=pointer-arith -Werror=write-strings -Werror=declaration-after-statement -Werror=implicit-function-declaration",
   "CXX"   =>"g++",
   "OBJEXT"   =>"o",
   "CPPFLAGS"   =>"   -I/home/geek/.rvm/rubies/ruby-1.9.3-p327/include",
   "LDFLAGS"   =>"-L.  -rdynamic -Wl, -export-dynamic -L/home/geek/.rvm/rubies/ruby-1.9.3-p327/lib  -Wl,-R/home/geek/.rvm/rubies/ruby-1.9.3-p327/lib ",
   "CFLAGS"   =>" -O3 -ggdb -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Werror=pointer-arith -Werror=write-strings -Werror=declaration-after-statement -Werror=implicit-function-declaration  -fPIC",
   "CC"   =>"gcc",
   "target_os"   =>"linux",
   "target_vendor"   =>"unknown",
   "target_cpu"   =>"x86_64",
   "target"   =>"x86_64-unknown-linux-gnu",
   "host_os"   =>"linux-gnu",
   "host_vendor"   =>"unknown",
   "host_cpu"   =>"x86_64",
   "host"   =>"x86_64-unknown-linux-gnu",
   "RUBYW_BASE_NAME"   =>"rubyw",
   "RUBY_BASE_NAME"   =>"ruby",
   "build_os"   =>"linux-gnu",
   "build_vendor"   =>"unknown",
   "build_cpu"   =>"x86_64",
   "build"   =>"x86_64-unknown-linux-gnu",
   "RUBY_RELEASE_DATE"   =>"2012-11-10",
   "RUBY_PROGRAM_VERSION"   =>"1.9.3",
   "BASERUBY"   =>"ruby",
   "mandir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share/man",
   "localedir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share/locale",
   "libdir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/lib",
   "psdir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share/doc/ruby",
   "pdfdir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share/doc/ruby",
   "dvidir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share/doc/ruby",
   "htmldir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share/doc/ruby",
   "infodir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share/info",
   "docdir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share/doc/ruby",
   "oldincludedir"   =>"/usr/include",
   "includedir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/include",
   "localstatedir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/var",
   "sharedstatedir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/com",
   "sysconfdir"   =>"/etc",
   "datadir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share",
   "datarootdir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/share",
   "libexecdir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/libexec",
   "sbindir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/sbin",
   "bindir"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327/bin",
   "exec_prefix"   =>"/home/geek/.rvm/rubies/ruby-1.9.3-p327",
   "SHELL"=>"/bin/bash",

}

usage.rb

require 'rbconfig' 
HOST_OS = RbConfig::CONFIG['host_os']