Mention --copy option for search command

README.md

@@ -139,3 +139,18 @@ A61B -- VAI SYMBOL DOONG -- ꘛ
 
 # Note: Capital C and Capital H are missing from UnicodeData.txt
 ```
+
+### Copy into clipboard ###
+
+Option `--copy` (compact form `-c`) can be used to copy the glyph directly into
+the clipboard when search return only one row:
+
+```console
+% piken search --copy door
+WARN[0000] Copy to clipboard not allowed for multiple rows.
+2F3E -- KANGXI RADICAL DOOR -- ⼾
+1F6AA -- DOOR -- 🚪
+
+% piken search --copy door NOT k*
+1F6AA -- DOOR -- 🚪
+```

doc.go

@@ -131,5 +131,18 @@ Specify column used to search
 	1D50F -- MATHEMATICAL FRAKTUR CAPITAL L -- 𝔏
 
 	# Note: Capital C and Capital H are missing from UnicodeData.txt
+
+Copy into clipboard
+
+Option "--copy" (compact form "-c") can be used to copy the glyph directly into
+the clipboard when search return only one row:
+
+	% piken search --copy door
+	WARN[0000] Copy to clipboard not allowed for multiple rows.
+	2F3E -- KANGXI RADICAL DOOR -- ⼾
+	1F6AA -- DOOR -- 🚪
+
+	% piken search --copy door NOT k*
+	1F6AA -- DOOR -- 🚪
 */
 package main // import "eriol.xyz/piken"