最新版的MacOS Sierra預設帶的python環境仍然為2.7.10，本文將介紹使用Brew安裝python3.5並做簡單的配置，打造python2，python3共存的開發環境
直接嘗試brew安裝，提示需要執行brew link gdbm
thatsitdeMacBook-Pro:~ thatsit$ brew install python3 Updating Homebrew... Error: You must `brew link gdbm` before python3 can be installed thatsitdeMacBook-Pro:~ thatsit$
按提示執行brew link gdbm，提示目錄許可權問題
thatsitdeMacBook-Pro:~ thatsit$ brew link gdbm Linking /usr/local/Cellar/gdbm/1.12... Error: Could not symlink share/man/man3/gdbm.3 /usr/local/share/man/man3 is not writable. thatsitdeMacBook-Pro:~ thatsit$
嘗試sudo執行brew，提示已經不再支援以root許可權執行
thatsitdeMacBook-Pro:~ thatsit$ sudo brew link gdbm Password: Error: Running Homebrew as root is extremely dangerous and no longer supported. As Homebrew does not drop privileges on installation you would be giving all build scripts full access to your system. thatsitdeMacBook-Pro:~ thatsit$
確認目錄許可權並調整
thatsitdeMacBook-Pro:~ thatsit$ ll /usr/local/share/man/man3/ total 240 -rw-rw-r-- 1 root wheel 25111 1 12 2014 cdt.3 -rw-rw-r-- 1 root wheel 27894 1 12 2014 cgraph.3 -rw-rw-r-- 1 root wheel 1762 1 12 2014 expr.3 -rw-rw-r-- 1 root wheel 2103 1 12 2014 gvc.3 -rw-rw-r-- 1 root wheel 2966 1 12 2014 gvpr.3 -rw-rw-r-- 1 root wheel 9628 1 12 2014 pack.3 -rw-rw-r-- 1 root wheel 5386 1 12 2014 pathplan.3 -rw-rw-r-- 1 root wheel 15026 1 12 2014 tcldot.3tcl -rw-rw-r-- 1 root wheel 7109 1 12 2014 tkspline.3tk -rw-rw-r-- 1 root wheel 8157 1 12 2014 xdot.3 thatsitdeMacBook-Pro:~ thatsit$ thatsitdeMacBook-Pro:~ thatsit$ sudo chown -R thatsit /usr/local/share/man/man3/ thatsitdeMacBook-Pro:~ thatsit$
再次執行，OK
thatsitdeMacBook-Pro:~ thatsit$ brew link gdbm Linking /usr/local/Cellar/gdbm/1.12... 12 symlinks created thatsitdeMacBook-Pro:~ thatsit$ thatsitdeMacBook-Pro:~ thatsit$ brew install python3 ==> Installing dependencies for python3: xz ==> Installing python3 dependency: xz ==> Downloading https://homebrew.bintray.com/bottles/xz-5.2.2.el_capitan.bottle.tar.gz ######################################################################## 100.0% ==> Pouring xz-5.2.2.el_capitan.bottle.tar.gz Error: The `brew link` step did not complete successfully The formula built, but is not symlinked into /usr/local Could not symlink lib/pkgconfig/liblzma.pc /usr/local/lib/pkgconfig is not writable. You can try again using: brew link xz ==> Summary ? /usr/local/Cellar/xz/5.2.2: 91 files, 1.4M ==> Installing python3 ==> Downloading https://homebrew.bintray.com/bottles/python3-3.5.2_3.el_capitan.bottle.tar.gz ######################################################################## 100.0%j ==> Pouring python3-3.5.2_3.el_capitan.bottle.tar.gz Error: The `brew link` step did not complete successfully The formula built, but is not symlinked into /usr/local Could not symlink lib/pkgconfig/python-3.5.pc /usr/local/lib/pkgconfig is not writable. You can try again using: brew link python3 ==> Using the sandbox ==> /usr/local/Cellar/python3/3.5.2_3/bin/python3 -s setup.py --no-user-cfg install --force --verbose --install-scripts=/usr/local/Cellar/python3/3.5.2_3/bin --install-lib=/usr/local/lib/python3.5/site-packages --single-version-externally-managed --record=installed.txt ==> /usr/local/Cellar/python3/3.5.2_3/bin/python3 -s setup.py --no-user-cfg install --force --verbose --install-scripts=/usr/local/Cellar/python3/3.5.2_3/bin --install-lib=/usr/local/lib/python3.5/site-packages --single-version-externally-managed --record=installed.txt ==> /usr/local/Cellar/python3/3.5.2_3/bin/python3 -s setup.py --no-user-cfg install --force --verbose --install-scripts=/usr/local/Cellar/python3/3.5.2_3/bin --install-lib=/usr/local/lib/python3.5/site-packages --single-version-externally-managed --record=installed.txt ==> Caveats Pip, setuptools, and wheel have been installed. To update them pip3 install --upgrade pip setuptools wheel You can install Python packages with pip3 install <package> They will install into the site-package directory /usr/local/lib/python3.5/site-packages See: https://github.com/Homebrew/brew/blob/master/docs/Homebrew-and-Python.md .app bundles were installed. Run `brew linkapps python3` to symlink these to /Applications. ==> Summary ? /usr/local/Cellar/python3/3.5.2_3: 3,498 files, 53.3M thatsitdeMacBook-Pro:~ thatsit$
新增python3環境變數
thatsitdeMacBook-Pro:~ thatsit$ tail -1 /etc/profile export PATH=/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/Cellar/python3/3.5.2_3/bin thatsitdeMacBook-Pro:~ thatsit$
測試
thatsitdeMacBook-Pro:bin thatsit$ python Python 2.7.10 (default, Oct 23 2015, 19:19:21) [GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.59.5)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> ^D thatsitdeMacBook-Pro:bin thatsit$ python3 Python 3.5.2 (default, Oct 11 2016, 05:05:28) [GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.38)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> thatsitdeMacBook-Pro:bin thatsit$
DONE