我安装了jupyter包，如下所示：
jscherman@lenovo-x1c:/usr/local/lib/python2.7/site-packages$ pip install jupyter
Collecting jupyter
Downloading https://files.pythonhosted.org/packages/83/df/0f5dd132200728a86190397e1ea87cd76244e42d39ec5e88efd25b2abd7e/jupyter-1.0.0-py2.py3-none-any.whl
Collecting nbconvert (from jupyter)
Downloading https://files.pythonhosted.org/packages/39/ea/280d6c0d92f8e3ca15fd798bbcc2ea141489f9539de7133d8fe10ea4b049/nbconvert-5.3.1-py2.py3-none-any.whl (387kB)
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Collecting ipywidgets (from jupyter)
Downloading https://files.pythonhosted.org/packages/7d/24/fabc09ad81c6071159a4d12d5bfbddcbea69bd9e3b16c3250ef300c0285f/ipywidgets-7.2.1-py2.py3-none-any.whl (106kB)
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Collecting notebook (from jupyter)
Downloading https://files.pythonhosted.org/packages/96/1f/e113875e6b8c8ee0e8c5748bf6fc942a109874adc9ca25248e95cf069803/notebook-5.4.1-py2.py3-none-any.whl (8.0MB)
1% |▋ | 153kB 912kB/s eta 0:00:09^C
Operation cancelled by user
jscherman@lenovo-x1c:/usr/local/lib/python2.7/site-packages$ clear
jscherman@lenovo-x1c:/usr/local/lib/python2.7/site-packages$ pip install jupyter
Collecting jupyter
Downloading https://files.pythonhosted.org/packages/83/df/0f5dd132200728a86190397e1ea87cd76244e42d39ec5e88efd25b2abd7e/jupyter-1.0.0-py2.py3-none-any.whl
Collecting nbconvert (from jupyter)
Downloading https://files.pythonhosted.org/packages/39/ea/280d6c0d92f8e3ca15fd798bbcc2ea141489f9539de7133d8fe10ea4b049/nbconvert-5.3.1-py2.py3-none-any.whl (387kB)
100% |████████████████████████████████| 389kB 130kB/s
Collecting ipywidgets (from jupyter)
Downloading https://files.pythonhosted.org/packages/7d/24/fabc09ad81c6071159a4d12d5bfbddcbea69bd9e3b16c3250ef300c0285f/ipywidgets-7.2.1-py2.py3-none-any.whl (106kB)
100% |████████████████████████████████| 112kB 981kB/s
Collecting notebook (from jupyter)
Downloading https://files.pythonhosted.org/packages/96/1f/e113875e6b8c8ee0e8c5748bf6fc942a109874adc9ca25248e95cf069803/notebook-5.4.1-py2.py3-none-any.whl (8.0MB)
100% |████████████████████████████████| 8.0MB 480kB/s
Collecting qtconsole (from jupyter)
Downloading https://files.pythonhosted.org/packages/90/ff/047e0dca2627b162866920e7aa93f04523c0ae81e5c67060eec85701992d/qtconsole-4.3.1-py2.py3-none-any.whl (108kB)
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Collecting jupyter-console (from jupyter)
Downloading https://files.pythonhosted.org/packages/77/82/6469cd7fccf7958cbe5dce2e623f1e3c5e27f1bb1ad36d90519bc2d5d370/jupyter_console-5.2.0-py2.py3-none-any.whl
Collecting ipykernel (from jupyter)
Downloading https://files.pythonhosted.org/packages/8e/65/c7ca3e3d05f9bd51b3010076b84f4e7304b12d0abf62a48f6cec2c90c019/ipykernel-4.8.2-py2-none-any.whl (108kB)
100% |████████████████████████████████| 112kB 650kB/s
Collecting pandocfilters>=1.4.1 (from nbconvert->jupyter)
Collecting entrypoints>=0.2.2 (from nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/cc/8b/4eefa9b47f1910b3d2081da67726b066e379b04ca897acfe9f92bac56147/entrypoints-0.2.3-py2.py3-none-any.whl
Requirement already satisfied: jinja2 in /usr/lib/python2.7/dist-packages (from nbconvert->jupyter) (2.8)
Collecting testpath (from nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/15/19/d7bc380c479a184e4a5a9ce516e4e2a773165f89b445f7cdced83d94de25/testpath-0.3.1-py2.py3-none-any.whl (161kB)
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Collecting mistune>=0.7.4 (from nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/c8/8c/87f4d359438ba0321a2ae91936030110bfcc62fef752656321a72b8c1af9/mistune-0.8.3-py2.py3-none-any.whl
Collecting nbformat>=4.4 (from nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/da/27/9a654d2b6cc1eaa517d1c5a4405166c7f6d72f04f6e7eea41855fe808a46/nbformat-4.4.0-py2.py3-none-any.whl (155kB)
100% |████████████████████████████████| 163kB 301kB/s
Collecting pygments (from nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/02/ee/b6e02dc6529e82b75bb06823ff7d005b141037cb1416b10c6f00fc419dca/Pygments-2.2.0-py2.py3-none-any.whl (841kB)
100% |████████████████████████████████| 849kB 1.2MB/s
Collecting bleach (from nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/30/b6/a8cffbb9ab4b62b557c22703163735210e9cd857d533740c64e1467d228e/bleach-2.1.3-py2.py3-none-any.whl
Collecting traitlets>=4.2 (from nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/93/d6/abcb22de61d78e2fc3959c964628a5771e47e7cc60d53e9342e21ed6cc9a/traitlets-4.3.2-py2.py3-none-any.whl (74kB)
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Collecting jupyter-core (from nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/1d/44/065d2d7bae7bebc06f1dd70d23c36da8c50c0f08b4236716743d706762a8/jupyter_core-4.4.0-py2.py3-none-any.whl (126kB)
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Collecting ipython<6.0.0,>=4.0.0; python_version < "3.3" (from ipywidgets->jupyter)
Downloading https://files.pythonhosted.org/packages/16/af/fbc5ecbb283344365ac98079524f8d61fd1b2afcef31d469023cba80b439/ipython-5.6.0-py2-none-any.whl (760kB)
100% |████████████████████████████████| 768kB 1.0MB/s
Collecting widgetsnbextension~=3.2.0 (from ipywidgets->jupyter)
Downloading https://files.pythonhosted.org/packages/ff/fa/64acc09fc845a6b2dc0724d6f3f81e829b778ed5e9a7559567b4f19a3f4b/widgetsnbextension-3.2.1-py2.py3-none-any.whl (2.2MB)
100% |████████████████████████████████| 2.2MB 2.0MB/s
Collecting Send2Trash (from notebook->jupyter)
Collecting ipython-genutils (from notebook->jupyter)
Downloading https://files.pythonhosted.org/packages/fa/bc/9bd3b5c2b4774d5f33b2d544f1460be9df7df2fe42f352135381c347c69a/ipython_genutils-0.2.0-py2.py3-none-any.whl
Collecting jupyter-client>=5.2.0 (from notebook->jupyter)
Downloading https://files.pythonhosted.org/packages/94/dd/fe6c4d683b09eb05342bd2816b7779663f71762b4fa9c2d5203d35d17354/jupyter_client-5.2.3-py2.py3-none-any.whl (89kB)
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Requirement already satisfied: tornado>=4 in /usr/lib/python2.7/dist-packages (from notebook->jupyter) (4.2.1)
Collecting terminado>=0.8.1 (from notebook->jupyter)
Downloading https://files.pythonhosted.org/packages/2e/20/a26211a24425923d46e1213b376a6ee60dc30bcdf1b0c345e2c3769deb1c/terminado-0.8.1-py2.py3-none-any.whl
Collecting prompt-toolkit<2.0.0,>=1.0.0 (from jupyter-console->jupyter)
Downloading https://files.pythonhosted.org/packages/d1/b0/1a6c262da35c779dd79550137aa7c298a424987240a28792ec5ccf48f848/prompt_toolkit-1.0.15-py2-none-any.whl (247kB)
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Collecting configparser>=3.5; python_version == "2.7" (from entrypoints>=0.2.2->nbconvert->jupyter)
Requirement already satisfied: MarkupSafe in /usr/lib/python2.7/dist-packages (from jinja2->nbconvert->jupyter) (0.23)
Collecting jsonschema!=2.5.0,>=2.4 (from nbformat>=4.4->nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/77/de/47e35a97b2b05c2fadbec67d44cfcdcd09b8086951b331d82de90d2912da/jsonschema-2.6.0-py2.py3-none-any.whl
Collecting html5lib!=1.0b1,!=1.0b2,!=1.0b3,!=1.0b4,!=1.0b5,!=1.0b6,!=1.0b7,!=1.0b8,>=0.99999999pre (from bleach->nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/a5/62/bbd2be0e7943ec8504b517e62bab011b4946e1258842bc159e5dfde15b96/html5lib-1.0.1-py2.py3-none-any.whl (117kB)
100% |████████████████████████████████| 122kB 782kB/s
Collecting six (from bleach->nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/67/4b/141a581104b1f6397bfa78ac9d43d8ad29a7ca43ea90a2d863fe3056e86a/six-1.11.0-py2.py3-none-any.whl
Requirement already satisfied: decorator in /usr/lib/python2.7/dist-packages (from traitlets>=4.2->nbconvert->jupyter) (4.0.6)
Collecting enum34; python_version == "2.7" (from traitlets>=4.2->nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/c5/db/e56e6b4bbac7c4a06de1c50de6fe1ef3810018ae11732a50f15f62c7d050/enum34-1.1.6-py2-none-any.whl
Requirement already satisfied: pexpect; sys_platform != "win32" in /usr/lib/python2.7/dist-packages (from ipython<6.0.0,>=4.0.0; python_version < "3.3"->ipywidgets->jupyter) (4.0.1)
Collecting backports.shutil-get-terminal-size; python_version == "2.7" (from ipython<6.0.0,>=4.0.0; python_version < "3.3"->ipywidgets->jupyter)
Downloading https://files.pythonhosted.org/packages/7d/cd/1750d6c35fe86d35f8562091737907f234b78fdffab42b29c72b1dd861f4/backports.shutil_get_terminal_size-1.0.0-py2.py3-none-any.whl
Requirement already satisfied: setuptools>=18.5 in /usr/lib/python2.7/dist-packages (from ipython<6.0.0,>=4.0.0; python_version < "3.3"->ipywidgets->jupyter) (20.7.0)
Collecting pathlib2; python_version == "2.7" or python_version == "3.3" (from ipython<6.0.0,>=4.0.0; python_version < "3.3"->ipywidgets->jupyter)
Downloading https://files.pythonhosted.org/packages/74/4e/68add57f8b993bb5da70c22c7eebb4266c7b66cab15095a1578cc6a62b1a/pathlib2-2.3.0-py2.py3-none-any.whl
Requirement already satisfied: simplegeneric>0.8 in /usr/lib/python2.7/dist-packages (from ipython<6.0.0,>=4.0.0; python_version < "3.3"->ipywidgets->jupyter) (0.8.1)
Collecting pickleshare (from ipython<6.0.0,>=4.0.0; python_version < "3.3"->ipywidgets->jupyter)
Downloading https://files.pythonhosted.org/packages/9f/17/daa142fc9be6b76f26f24eeeb9a138940671490b91cb5587393f297c8317/pickleshare-0.7.4-py2.py3-none-any.whl
Requirement already satisfied: pyzmq>=13 in /usr/lib/python2.7/dist-packages (from jupyter-client>=5.2.0->notebook->jupyter) (15.2.0)
Collecting python-dateutil>=2.1 (from jupyter-client>=5.2.0->notebook->jupyter)
Downloading https://files.pythonhosted.org/packages/0c/57/19f3a65bcf6d5be570ee8c35a5398496e10a0ddcbc95393b2d17f86aaaf8/python_dateutil-2.7.2-py2.py3-none-any.whl (212kB)
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Requirement already satisfied: ptyprocess; os_name != "nt" in /usr/lib/python2.7/dist-packages (from terminado>=0.8.1->notebook->jupyter) (0.5)
Collecting wcwidth (from prompt-toolkit<2.0.0,>=1.0.0->jupyter-console->jupyter)
Downloading https://files.pythonhosted.org/packages/7e/9f/526a6947247599b084ee5232e4f9190a38f398d7300d866af3ab571a5bfe/wcwidth-0.1.7-py2.py3-none-any.whl
Collecting functools32; python_version == "2.7" (from jsonschema!=2.5.0,>=2.4->nbformat>=4.4->nbconvert->jupyter)
Collecting webencodings (from html5lib!=1.0b1,!=1.0b2,!=1.0b3,!=1.0b4,!=1.0b5,!=1.0b6,!=1.0b7,!=1.0b8,>=0.99999999pre->bleach->nbconvert->jupyter)
Downloading https://files.pythonhosted.org/packages/f4/24/2a3e3df732393fed8b3ebf2ec078f05546de641fe1b667ee316ec1dcf3b7/webencodings-0.5.1-py2.py3-none-any.whl
Collecting scandir; python_version < "3.5" (from pathlib2; python_version == "2.7" or python_version == "3.3"->ipython<6.0.0,>=4.0.0; python_version < "3.3"->ipywidgets->jupyter)
Installing collected packages: pandocfilters, configparser, entrypoints, testpath, mistune, ipython-genutils, six, enum34, traitlets, jupyter-core, functools32, jsonschema, nbformat, pygments, webencodings, html5lib, bleach, nbconvert, wcwidth, prompt-toolkit, backports.shutil-get-terminal-size, scandir, pathlib2, pickleshare, ipython, Send2Trash, python-dateutil, jupyter-client, terminado, ipykernel, notebook, widgetsnbextension, ipywidgets, qtconsole, jupyter-console, jupyter
然后，当我尝试运行它时，我得到了
jscherman@lenovo-x1c:/usr/local/lib/python2.7/site-packages$ jupyter notebook
jupyter: command not found
让我们看看原因：
jscherman@lenovo-x1c:/usr/local/lib/python2.7/site-packages$ pip list
Package Version
------------------ -------
adium-theme-ubuntu 0.3.4
decorator 4.0.6
ipython 2.4.1
Jinja2 2.8
MarkupSafe 0.23
meld 3.14.2
pexpect 4.0.1
pip 10.0.0
ptyprocess 0.5
pycurl 7.43.0
pygobject 3.20.0
PyMySQL 0.7.2
pyzmq 15.2.0
setuptools 20.7.0
simplegeneric 0.8.1
tornado 4.2.1
unity-lens-photos 1.0
wheel 0.29.0
为什么它不会出现在列表中？一点背景：
jscherman@lenovo-x1c:/usr/local/lib/python2.7/site-packages$ python --version
Python 2.7.12
jscherman@lenovo-x1c:/usr/local/lib/python2.7/site-packages$ pip --version
pip 10.0.0 from /home/jscherman/.local/lib/python2.7/site-packages/pip (python 2.7)
知道发生了什么事吗？任何帮助将受到高度赞赏。