起動時のメッセージ Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
と記載されている通り jupyter notebookを終了したい場合は、起動したコマンドプロンプト上でCtrl+Cキーを入力してください。
入力可能な状態に戻ります。
DOS
1C:\Windows\system32>jupyter notebook
2[I 13:14:53.450 NotebookApp] [nb_conda_kernels] enabled, 6 kernels found
3[I 13:15:14.587 NotebookApp] [nb_anacondacloud] enabled
4[I 13:15:14.686 NotebookApp] [nb_conda] enabled
5[I 13:15:15.885 NotebookApp] \u2713 nbpresent HTML export ENABLED
6[W 13:15:15.903 NotebookApp] \u2717 nbpresent PDF export DISABLED: No module named 'nbbrowserpdf'
7[I 13:15:16.320 NotebookApp] Serving notebooks from local directory: C:/~
8[I 13:15:16.320 NotebookApp] 0 active kernels
9[I 13:15:16.321 NotebookApp] The Jupyter Notebook is running at:
10[I 13:15:16.321 NotebookApp] http://localhost:8888/?token=~
11[I 13:15:16.321 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
12[C 13:15:16.328 NotebookApp]
1314 Copy/paste this URL into your browser when you connect for the first time,
15 to login with a token:
16 http://localhost:8888/?token=~
17[I 13:15:16.695 NotebookApp] Accepting one-time-token-authenticated connection from ::1
18(Ctrl+Cキーが入力された)
19[I 13:17:11.328 NotebookApp] Interrupted...
20[I 13:17:11.328 NotebookApp] Shutting down 0 kernels
2122C:\Windows\system32>