update doc for realtime plot using cli example

README.rst

@@ -115,6 +115,26 @@ Feed it data points via stdin:
 
 ..
 
+Realtime graph for data points via stdin:
+
+::
+
+ $ ping -i.2 google.com | grep -oP '(?<=time=).*(?=ms)' --line-buffered | asciigraph -r -h 10 -w 40 -c "realtime plot data (google ping in ms) from stdin"
+ 8.26 ┤                 ╭╮
+ 7.77 ┤                 ││
+ 7.27 ┤                 ││
+ 6.78 ┤                 ││             ╭╮
+ 6.29 ┤    ╭╮ ╭╮        ││             ││
+ 5.79 ┤    ││ ││        ││             │╰╮
+ 5.30 ┤    ││ ││      ╭╮││             │ │   ╭
+ 4.81 ┤    ││ ││      ││││             │ │   │
+ 4.32 ┤ ╭╮ ││╭╯│   ╭╮ ││││             │ │  ╭╯
+ 3.82 ┼╮│╰─╯╰╯ │╭──╯╰─╯╰╯╰──╮ ╭───╮╭───╯ ╰──╯
+ 3.33 ┤╰╯      ╰╯           ╰─╯   ╰╯
+         realtime plot data (google ping in ms) from stdin
+
+..
+
 
 Acknowledgement
 ----------------