Index: usr.bin/grep/grep.1
===================================================================
--- usr.bin/grep/grep.1
+++ usr.bin/grep/grep.1
@@ -30,7 +30,7 @@
 .\"
 .\"	@(#)grep.1	8.3 (Berkeley) 4/18/94
 .\"
-.Dd August 21, 2018
+.Dd May 13, 2019
 .Dt GREP 1
 .Os
 .Sh NAME
@@ -137,7 +137,7 @@
 no whitespace may be given between the option and its argument.
 .It Fl c , Fl Fl count
 Only a count of selected lines is written to standard output.
-.It Fl Fl colour= Ns Oo Ar when Oc , Fl Fl color= Ns Oo Ar when Oc
+.It Fl Fl colour Ns Oo Cm = Ns Ar when Oc , Fl Fl color Ns Oo Cm = Ns Ar when Oc
 Mark up the matching text with the expression stored in the
 .Ev GREP_COLOR
 environment variable.
@@ -145,9 +145,14 @@
 .Ar when
 are
 .Dq Cm never ,
-.Dq Cm always
+.Dq Cm always ,
 and
 .Dq Cm auto .
+The default value is
+.Dq Cm auto
+in case
+.Ar when
+is not set.
 .It Fl D Ar action , Fl Fl devices= Ns Ar action
 Specify the demanded
 .Ar action