• $! - latest error message
  • $@ - location of error
  • $_ - string last read by gets
  • $. - line number last read by interpreter
  • $& - string last matched by regexp
  • $~ - the last regexp match, as an array of subexpressions
  • $n - the nth subexpression in the last match (same as $~[n])
  • $= - case-insensitivity flag
  • $/ - input record separator
  • $\ - output record separator
  • $0 - the name of the ruby script file
  • $* (or ARGV) - the command line arguments
  • $$ - interpreter’s process ID
  • $? - exit status of last executed child process
  • $-i $-l $-p $-v - Command line switches
  • $-v (or $VERBOSE) - verbose mode