Full_Name: G. Grothendieck Version: R 1.9.1 patched 2004-07-13 OS: Windows XP Submission from: (NULL) (209.226.152.23) The following command causes R to crash every time: sub("(.) (.)", "\\1 \\2 \\3", "abc", perl = TRUE) on Windows XP R version 1.9.1 patched version of 2004-07-13.