Python3.6 installation and pit avoidance guide for Linux

The installation of Python3

1. Install dependent environments

Python3 may use various dependency libraries during the installation process, so you need to install these dependencies before installing Python3.

yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel
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2. Download Python3 source code

There are two ways to download the Python3 source code. One is from the Python3 website:

https://www.python.org/downloads/source/
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Another option is to download it directly via wget, such as the following command:

Wget HTTP: / / https://www.python.org/ftp/python/3.6.1/Python-3.6.1.tgzCopy the code

3. Create an installation directory

The installation directory can be created to your liking, such as in /usr/local/python3:

mkdir -p /usr/local/python3
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4. Decompress the source package

Decompress the source package downloaded in step 2 as follows:

The tar ZXVF Python - 3.6.1. TGZCopy the code

5. Compile source code

Enter the directory of decompressed source package first, and then configure:

CD Python - 3.6.1. / configure -- prefix = / usr/local/python3Copy the code

Then compile, then install:

make
make install
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6. Set up the Python3 soft link

ln -s /usr/local/python3/bin/python3 /usr/bin/python3
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7. Add /usr/local/python3/bin to PATH

Edit bash_profile to modify environment variables:

vim ~/.bash_profile
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Add the Python3 startup directory under the PATH variable:

# .bash_profile

# Get the aliases and functions
if [ -f ~/.bashrc ]; then
        . ~/.bashrc
fi

# User specific environment and startup programs

PATH=$PATH:$HOME/bin:/usr/local/python3/bin

export PATH
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After the modification is complete, press Esc and enter :wq to save the configuration and exit.

8. Check whether Python3 and Pip3 are available

Execute the following command (note that V is uppercase V). If you see the same results, Python3 has been installed successfully.

[alvin@VM_0_16_centos ~]$python3 -v Python 3.6.1 [alvin@VM_0_16_centos ~]$pip3 -v PIP 9.0.1 from / usr/local/lib/python3.6 / site - packages (python 3.6)Copy the code

Avoid pit guide

In fact, there are so many posts on the Internet about Python3 installation that the steps are pretty much the same. However, after the actual hands-on installation, there is more or less a bit of trouble, especially for beginners. Here are some common ones:

Crater 1: configure: error: no acceptable C compiler found in $PATH

The problem is simply the lack of a GCC compilation environment. Install GCC:

yum install -y gcc
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Of course, in addition to the use of source code installation can also be.

2: the pit zipimport. ZipImportError: can ‘t decompress the data

This problem is caused by the lack of zlib toolkits.

yum -y install zlib*
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Recompile the source code after installation, can be solved.

Pit 3: PIp3: Can’t connect to HTTPS URL because the SSL Module is not available

Pip3 requires the SSL module, and this function is unavailable because it is not specified./configure does not include the — with-ssl parameter. The solutions are as follows:

CD python-3.6.2./configure --with-ssl make sudo make installCopy the code

Pit 4: Multilib version Problems

There are multiple versions of the same library. Just delete the extra version.

Query the existing version first (take OpenSSL as an example, check which version conflicts)

# RPM - qa | grep openssl openssl devel - 1.0.0-27 el6_4. 2. X86_64 openssl 1.0.0-27 el6_4. 2. X86_64 Openssl 1.0.0-27. El6_4. 2. I686Copy the code

Openssl-1.0.0-27.el6_4.2.x86_64 openSSL-1.0.0-27.el6_4.2.i686 openSSL: openSSL-1.0.0-27.el6_4.2.i686 openSSL: openSSL-1.0.0-27.el6_4.2.i686 openSSL: openSSL-1.0.0-27.el6_4.2.i686

RPM -- erase -- nodeps openssl 1.0.0-27 el6_4. 2. I686Copy the code

Update openSSL:

# yum update "openssl*"
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Query openSSL again, problem solved!

# RPM - qa | grep openssl openssl devel - e - 16. 1.0.1 el6_5. 7. X86_64 openssl - e - 16 1.0.1. El6_5. 7. X86_64Copy the code