\       Quote the next metacharacter
  []      Character class
  {}      Multiple pattern
  *       Match any string of characters
  ?       Match any single character
  ~       User name home directory

The metanotation a{b,c,d}e is a shorthand for abe ace ade. Left to right order is preserved, with results of matches being sorted separately at a low level to preserve this order. As a special case {, }, and {} are passed undisturbed.