Python，virtualenv和linux - noob to all 3。
我有一个小的python项目，它使用/usr/local/lib/python2.7/dist-packages内的下载包（PyFPDF）。一切正常。
我读过使用virtualenv是一个更好的方法，因为它保持项目和项目相关的包彼此分离和主要的python系统。
所以我已经设置了virtualenv，我现在有：
~/python/project/folder
|_py script file
|_folder with some project related files
|_env folder
$ ls env/lib/python2.7/site-packages
|_folder 'fpdf' & 'fpdf-1.7.2.egg-info'
|_others too but not not relevant here
然而，当我运行脚本时，我收到一条关于丢失PIL的消息。
我看到PIL实际上位于原始的python设置中。
/usr/lib/python2.7/dist-packages/
我的env设置根本没有dist-packages文件夹 - 链接或其他我认为是整点，即env使用通用的系统范围的python包，但允许你使用项目特定的包。
我对原始设置如何工作感到困惑，因为如上所述，我从/usr/local/lib/python2.7/dist-packages/运行，其中没有PIL。
显然，我不明白以下之间的细微差别：
/usr/local/lib/python2.7/dist-packages/（没有PIL）和
/usr/lib/python2.7/dist-packages/（有PIL）
无论如何，长期和短期是让我的项目在env中运行我在shortcut内创建了/pythonproject/env/lib/python2.7/链接到/usr/lib/python2.7/dist-packages/
脚本现在运行得很完美，但我不禁觉得我已经入侵了它，我并没有真正的精神使用virtualenv。
我希望我的描述比泥浆更清晰。正如我所说的那样，我在这3条战线上都是一个菜鸟，但我正在给它一个裂缝。希望有人可以提供帮助。
编辑：所以这些是我的命令行
user@dual-lt ~ $ cd /home/user/Documents/PyProjects/PDFproject
user@dual-lt ~/Documents/PyProjects/PDFproject $ ls env
bin include lib local
user@dual-lt ~/Documents/PyProjects/PDFproject $ source env/bin/activate
(env)user@dual-lt ~/Documents/PyProjects/PDFproject $ which python
/home/user/Documents/PyProjects/PDFproject/env/bin/python
(env)user@dual-lt ~/Documents/PyProjects/PDFproject $ which pip
/home/user/Documents/PyProjects/PDFproject/env/bin/pip
(venv)user@dual-lt ~/Documents/PyProjects/PDFproject $ pip install pil
Requirement already satisfied (use --upgrade to upgrade): pil in /usr/lib/python2.7/dist-packages/PIL
Cleaning up...
(venv)user@dual-lt ~/Documents/PyProjects/PDFproject $
第二次编辑：
Downloading/unpacking pil
You are installing a potentially insecure and unverifiable file. Future versions of pip will default to disallowing insecure files.
Downloading PIL-1.1.7.tar.gz (506kB): 506kB downloaded
Running setup.py egg_info for package pil
WARNING: '' not a valid package name; please use only.-separated package names in setup.py
Installing collected packages: pil
Running setup.py install for pil
WARNING: '' not a valid package name; please use only.-separated package names in setup.py
building '_imaging' extension
x86_64-linux-gnu-gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fPIC -IlibImaging -I/home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/include -I/usr/local/include -I/usr/include -I/usr/include/python2.7 -c _imaging.c -o build/temp.linux-x86_64-2.7/_imaging.o
_imaging.c:75:20: fatal error: Python.h: No such file or directory
#include "Python.h"
^
compilation terminated.
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1
Complete output from command /home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/bin/python -c "import setuptools;__file__='/home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/build/pil/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-GxHMlW-record/install-record.txt --single-version-externally-managed --install-headers /home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/include/site/python2.7:
WARNING: '' not a valid package name; please use only.-separated package names in setup.py
running install
running build
running build_py
creating build
creating build/lib.linux-x86_64-2.7
copying PIL/__init__.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageFile.py -> build/lib.linux-x86_64-2.7
copying PIL/XbmImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageQt.py -> build/lib.linux-x86_64-2.7
copying PIL/GbrImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/XVThumbImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/CurImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/PalmImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageEnhance.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageFileIO.py -> build/lib.linux-x86_64-2.7
copying PIL/PSDraw.py -> build/lib.linux-x86_64-2.7
copying PIL/ArgImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/MicImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/PpmImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/PngImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageDraw2.py -> build/lib.linux-x86_64-2.7
copying PIL/TgaImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/FpxImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/FitsStubImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/FontFile.py -> build/lib.linux-x86_64-2.7
copying PIL/IptcImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/GimpGradientFile.py -> build/lib.linux-x86_64-2.7
copying PIL/GribStubImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageFilter.py -> build/lib.linux-x86_64-2.7
copying PIL/BdfFontFile.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageOps.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageMode.py -> build/lib.linux-x86_64-2.7
copying PIL/GdImageFile.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageCms.py -> build/lib.linux-x86_64-2.7
copying PIL/JpegImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImagePalette.py -> build/lib.linux-x86_64-2.7
copying PIL/ImagePath.py -> build/lib.linux-x86_64-2.7
copying PIL/BufrStubImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageWin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/Image.py -> build/lib.linux-x86_64-2.7
copying PIL/ExifTags.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageSequence.py -> build/lib.linux-x86_64-2.7
copying PIL/OleFileIO.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageGL.py -> build/lib.linux-x86_64-2.7
copying PIL/BmpImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/IcnsImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/PaletteFile.py -> build/lib.linux-x86_64-2.7
copying PIL/PsdImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/GimpPaletteFile.py -> build/lib.linux-x86_64-2.7
copying PIL/PcdImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/IcoImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImtImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/SunImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageFont.py -> build/lib.linux-x86_64-2.7
copying PIL/ContainerIO.py -> build/lib.linux-x86_64-2.7
copying PIL/PcxImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/SgiImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageGrab.py -> build/lib.linux-x86_64-2.7
copying PIL/WalImageFile.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageTransform.py -> build/lib.linux-x86_64-2.7
copying PIL/MspImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/MpegImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageDraw.py -> build/lib.linux-x86_64-2.7
copying PIL/EpsImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageColor.py -> build/lib.linux-x86_64-2.7
copying PIL/TiffImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageMath.py -> build/lib.linux-x86_64-2.7
copying PIL/PixarImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageTk.py -> build/lib.linux-x86_64-2.7
copying PIL/TiffTags.py -> build/lib.linux-x86_64-2.7
copying PIL/TarIO.py -> build/lib.linux-x86_64-2.7
copying PIL/DcxImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/McIdasImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/WmfImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/FliImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/Hdf5StubImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/PdfImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/SpiderImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/GifImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageChops.py -> build/lib.linux-x86_64-2.7
copying PIL/XpmImagePlugin.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageShow.py -> build/lib.linux-x86_64-2.7
copying PIL/ImageStat.py -> build/lib.linux-x86_64-2.7
copying PIL/PcfFontFile.py -> build/lib.linux-x86_64-2.7
running build_ext
building '_imaging' extension
creating build/temp.linux-x86_64-2.7
creating build/temp.linux-x86_64-2.7/libImaging
x86_64-linux-gnu-gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fPIC -IlibImaging -I/home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/include -I/usr/local/include -I/usr/include -I/usr/include/python2.7 -c _imaging.c -o build/temp.linux-x86_64-2.7/_imaging.o
_imaging.c:75:20: fatal error: Python.h: No such file or directory
#include "Python.h"
^
compilation terminated.
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1
----------------------------------------
Cleaning up...
Command /home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/bin/python -c "import setuptools;__file__='/home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/build/pil/setup.py'
exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-GxHMlW-record/install-record.txt --single-version-externally-managed --install-headers /home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/include/site/python2.7 failed with error code 1 in /home/dan/Documents/PyProjects/PDF-IdCardStatic/venv/build/pil
Storing complete log in /home/dan/.pip/pip.log`