1 files changed, 4 insertions, 0 deletions
diff --git a/sed.md b/sed.md
index e2cc9bd..3122058 100644
--- a/sed.md
+++ b/sed.md
@@ -7,3 +7,7 @@ Typical substitution:
 Can do multiple:
 
     sed -e 's/pattern/replacement/flags; s/bla/ble/'
+
+Back references require extended regexes:
+
+    sed -r -e 's/"(\w+)"/\1/'