Tweeted twitter.com/#!/StackCodeGolf/status/422891293686366208 occurred Jan 14 '14 at 0:41 5 edited tags | link edited Jan 13 '14 at 22:21 boothby 8,04022755 4 This is asking for shortest regex, which is akin to code-golf. | link edit approved Jan 13 '14 at 21:42 Cruncher 1,6131322 3 added 30 characters in body edited Jan 13 '14 at 17:42 xem 4,21111836 Your mission is to write the shortest valid regular expression that no string can match, empty string included. Submissions must have this form ("literal notation"): /pattern/optional-flags  Shortest regexp wins. The regexp size is counted in characters. (including slashes and flags) Please explain how your regexp works (if it's not trivial) Thanks, and have fun! Your mission is to write the shortest valid regular expression that no string can match, empty string included. Submissions must have this form ("literal notation"): /pattern/optional-flags  Shortest regexp wins. The regexp size is counted in characters. Please explain how your regexp works (if it's not trivial) Thanks, and have fun! Your mission is to write the shortest valid regular expression that no string can match, empty string included. Submissions must have this form ("literal notation"): /pattern/optional-flags  Shortest regexp wins. The regexp size is counted in characters. (including slashes and flags) Please explain how your regexp works (if it's not trivial) Thanks, and have fun! 2 Updated tags | link edited Jan 13 '14 at 17:37 ProgramFOX 6,83253766 1 asked Jan 13 '14 at 17:19 xem 4,21111836