View > Toggle line numbers

[gnestor]

Implementation of #1312. I moved the button from the toolbar to the View menu.

[gnestor]

Added line number config persistence thanks to @Carreau and c040464

[gnestor]

@Carreau I think this is ready to merge if you would like to have the honors...

[rgbkrk]

Wonderful.

[ellisonbg]

Merged!

[maver1ck]

Is there an option to make line numbers enabled by default ?

[rgbkrk]

@maver1ck In your ~/.jupyter/nbconfig/notebook.jsonset:

{
  "Cell": {
    "cm_config": {
      "lineNumbers": true
    }
  }
}

[juhasch]

Or run this in Python once (use 'CodeCell' if you want line numbers only in code cells):

from notebook.services.config import ConfigManager
c = ConfigManager()
c.update('notebook', {"CodeCell": {"cm_config": {"lineNumbers": True}}})

(Thanks to @takluyver in #2040)