diff --git a/docs/man/readtags.1.rst b/docs/man/readtags.1.rst
index d6f619b787..9c109a27c3 100644
--- a/docs/man/readtags.1.rst
+++ b/docs/man/readtags.1.rst
@@ -72,6 +72,15 @@ Controlling the Output
 By default, the output of readtags contains only the name, input and pattern
 field. The Output can be tweaked using these options:
 
+``-C``, ``--canonicalize-input``
+	Reduct '..' and '.' in input fields of regular tags.
+	This option works only with tags files having ``!_TAG_PROC_CWD`` pseudo
+	tag.
+
+	NOTE: The current implementation accepts only ``!_TAG_PROC_CWD``
+	starting with ``/``; a Windows directory name starting with a
+	drive letter like ``C:\Somewhere`` is not acceptable.
+
 ``-d``, ``--debug``
 	Turn on debugging output.
 
diff --git a/man/readtags.1.rst.in b/man/readtags.1.rst.in
index 7cf70a5919..107cd362a8 100644
--- a/man/readtags.1.rst.in
+++ b/man/readtags.1.rst.in
@@ -72,6 +72,15 @@ Controlling the Output
 By default, the output of readtags contains only the name, input and pattern
 field. The Output can be tweaked using these options:
 
+``-C``, ``--canonicalize-input``
+	Reduct '..' and '.' in input fields of regular tags.
+	This option works only with tags files having ``!_TAG_PROC_CWD`` pseudo
+	tag.
+
+	NOTE: The current implementation accepts only ``!_TAG_PROC_CWD``
+	starting with ``/``; a Windows directory name starting with a
+	drive letter like ``C:\Somewhere`` is not acceptable.
+
 ``-d``, ``--debug``
 	Turn on debugging output.