For anyone used to PC editing keys using a Mac, get an external keyboard and add some key bindings[0], you'll be much happier. (It also works on MacBook/Pro keyboard but they have tiny cursor keys.)

TL;DR create ~/Library/KeyBindings/DefaultKeyBinding.dict containing:

  {
        "\UF729"  = "moveToBeginningOfLine:";                   /* Home         */
        "\UF72B"  = "moveToEndOfLine:";                         /* End          */
        "$\UF729" = "moveToBeginningOfLineAndModifySelection:"; /* Shift + Home */
        "$\UF72B" = "moveToEndOfLineAndModifySelection:";       /* Shift + End  */
  }

[0] https://apple.stackexchange.com/questions/16135/remap-home-a...