linux系统环境变量和用户环境变量

Question

I have been confused with the question that why user environment variables can't work if system environment variables existing.

Rencently i installed and configured the python2.7 in linux. There was a python version 2.6.7 in linux

/usr/local/bin/python

so I had to set environment variable. Through internet I obtained the means to set the path

vi ~/.bash_profile(vi ~/.bashrc)
#add export PATH=$PATH:path_python_installed
source /etc/profile

But I have no idea why it doen't work. My solution is

#add alias python=path_python_installed/python

R installation was the same.

Answer 1

If you have a path in $PATH which already contains the 2.6.7 version, it will find that binary first.

Try echo $PATH and see if any of those paths include the older Python binary. You might want to set PATH to;

export PATH=path_to_new_python:$PATH

Answer 2

You have to add the new search path to the front of PATH:

 export PATH=/my/new/python/installation/bin:$PATH

When you enter python at the command prompt, the shell tries to find a file name python in any of the folders that are listed in $PATH. The first match will be used.

Answer 3

Drop the #add in front of the export and the alias commands. # is used to start a comment in Bash script. Wherever you found these, he must have added the #add as simply a directive.

UPDATE: You will also want to do what Bernhard has mentioned in his answer.