Default python path linux

What is Python path?

PYTHONPATH is an environment variable which the user can set to add additional directories that the user wants Python to add to the sys.path directory list. In short, we can say that it is an environment variable that you set before running the Python interpreter. Mostly you should not set these variables as they are not needed for Python to execute normal programs because it knows where its standard library is to be found. PYTHONPATH is used to help in importing the modules. So, when you import modules in your Python scripts, PYTHONPATH is also checked to see which directories might contain the imported module.

How to add to the PYTHONPATH in windows?

• My Computer > Properties > Advanced System Settings > Environment Variables >
• Click the “New” button in the top half of the dialog, to make a new user variable.
• Give the variable name as PYTHONPATH and the value is the path to the code directory.

To confirm PYTHONPATH, open Command Prompt and type :

NOTE:- Don’t confuse it with Python PATH environment variable. That is used to assist OS in calling an executable from anywhere which means if you just type Python on your Command Window, the system will look into the PATH to see which directories might contain an executable named python.

Setting the path for Python:

Windows allows environment variables to be configured permanently at both User level as well as the System level, or temporarily in a command prompt.

To run Python properly from a Command Prompt, you might choose to change some default environment variables in windows.

• To temporarily set environment variables, open Command Prompt and use the “set” command:

C:\> set PATH=” Directory of your python folder in C: drive”; %path%

How to set the Python path in windows:

• My Computer > Properties > Advanced System Settings > Environment Variables > Edit.
• Add python’s path to the end of the given directory ending with a semicolon (;)

How to set Python path in Unix or Linux:

To add the Python directory to the path for a particular session in Unix or Linux

• In the cshshell : type setenv PATH «$PATH:/usr/local/bin/python» and press Enter.
• In the bash shell (Linux) :type export PATH=»$PATH:/usr/local/bin/python» and press Enter.
• In the sh or kshshell :type PATH=»$PATH:/usr/local/bin/python» and press Enter.

NOTE:- /usr/local/bin/python is the path of the Python directory.

Источник

Add Python to Path in Linux

This article will cover four things: explain what PATH is in Linux, how to add Python to PATH, work on an example to demonstrate concepts, and lastly, for your convenience, discuss removing a directory from PATH.

What is PATH in Linux

PATH is an environment variable that contains a list of paths separated by a colon on Linux and a semi-colon in Windows.

Programs use the PATH variable to locate binaries (“executables”). For example, when you start Python from the terminal, the program will search for Python binaries in predefined directories. Among places to search are paths provided in PATH.

You can view the directories in PATH by running the following command on the terminal.

Most executable binaries are located at bin/, /usr/bin, /usr/local/bin, and /local/bin. These paths are already on the PATH (as shown above). That means most programs (including Python – see Figure below) should easily be started from the terminal using the executable’s name.

Adding a path into the PATH variable in Linux

If you’re using bash, add this line to your .bashrc located in the home directory

For example, the following line adds /usr/.local/bin/python to the PATH.

Save the .bashrc file and run the following command to refresh your bash session.

Note: You can run this command to accomplish all the above:

Alternatively, you can add a path directly from the shell. Depending on the shell type, a directory can be added by running any of the following commands on the terminal:

Example

In this example, we start by installing Python 3.11 on the Desktop – on a directory that is not in PATH.

Immediately after installing this Python, I got this warning:

WARNING: The scripts pip3.10 and pip3.11 are installed in '/home/kiprono/Desktop/python311/bin' which is not on PATH. Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.

Python 3.11 is installed in the bin folder. We need to add that folder into PATH; then, we can simply run “python3.11” to wake up this Python. We can do that by running the following:

Removing a directory from the PATH

You can run this command on the terminal to remove a folder from PATH.

PATH = $ ( REMOVE_PART = «/path/to/remove» sh — c ‘echo «:$PATH:» | sed «s@:$REMOVE_PART:@:@g;s@^: \ ( . * \ ) :\$@\1@»‘ )

Note: You may also have to remove the path from the .bashrc file to have a directory deleted from the PATH completely.

Conclusion

PATH is an environment variable containing a list of paths searched when looking for program executables. Adding Python to PATH means adding the location to the Python binary into the environment. This is done by running the following command on the terminal export PATH=/path/to/add:$PATH.

Источник

How to set Python environment variable PYTHONPATH on Linux?

Determine the path to your Python module or package. For example, suppose you have a Python module named mymodule located in the /home/user/myproject folder.

Set the PYTHONPATH environment variable to the path of your module or package using the following command −

$export PYTHONPATH=/home/user/myproject:$

This command sets the PYTHONPATH environment variable to /home/user/myproject and also includes the previous value of PYTHONPATH in case it was already set.

Note that the path should be separated by a colon (:) on Linux.

Verify that the PYTHONPATH environment variable has been set correctly using the following command −

This should display the path you set earlier, along with any previous paths that were included in PYTHONPATH.

Let us consider few more examples of setting the PYTHONPATH environment variable on Linux −

Set PYTHONPATH to a single path −

$export PYTHONPATH=/path/to/your/python/module

Set PYTHONPATH to multiple paths −

$export PYTHONPATH=/path/to/your/first/python/module:/path/to/your/second/python/module

Set PYTHONPATH to include the current directory −

$export PYTHONPATH=.:$PYTHONPATH

Set PYTHONPATH to include the current directory and a subdirectory −

$export PYTHONPATH=. /subdir:$PYTHONPATH

This sets the PYTHONPATH environment variable to include the current directory (.) and a subdirectory named subdir located in the current directory.

Note that the PYTHONPATH environment variable only affects the current shell session. If you want to set it permanently, you will need to add the export command to a startup script such as .bashrc or .bash_profile.

Determine the location of the folder containing the Python module or package that you want to add to the PYTHONPATH environment variable. For example, let’s say you have a folder called my_module located in your home directory (~/my_module).

Export the PYTHONPATH environment variable to include the folder containing the module or package, using the export command. For example, to add the ~/my_module folder to the PYTHONPATH environment variable, you can run the following command −

$export PYTHONPATH=$PYTHONPATH:~/my_module

The $PYTHONPATH variable is used to append the new folder to the existing value of PYTHONPATH, so that any previously set paths are not overwritten. The colon (:) is used to separate the new path from the existing paths.

It must be noted that this command will only set the PYTHONPATH environment variable for the current terminal session. To make this setting permanent, you will need to add it to your shell’s configuration file (e.g., ~/.bashrc for Bash).

Verify that the PYTHONPATH environment variable has been set correctly. You can do this by running the following command −

This should display the current value of the PYTHONPATH environment variable, including the folder you just added.

Adding multiple folders to PYTHONPATH

$export PYTHONPATH=$PYTHONPATH:~/my_module:~/my_other_module

This will add both the ~/my_module and ~/my_other_module folders to the PYTHONPATH environment variable.

Adding a folder with a space in its path name −

$export PYTHONPATH=$PYTHONPATH:"/path/with/space/my_module"

Note the use of double quotes to enclose the path name containing spaces.

Adding a folder relative to the current directory −

$export PYTHONPATH=$PYTHONPATH:./my_module

This will add the my_module folder located in the current directory to the PYTHONPATH environment variable.

Setting PYTHONPATH to a specific folder only −

$export PYTHONPATH=/path/to/my_module

This will set the PYTHONPATH environment variable to only contain the my_module folder located at /path/to/.

By setting the PYTHONPATH environment variable, you can ensure that Python can find and import the modules and packages you need for your projects, even if they are located outside of the default search paths.

Adding a package that requires a specific version of Python −

$export PYTHONPATH=$PYTHONPATH:/path/to/my_package

If you have multiple versions of Python installed on your system and you want to use a package that requires a specific version, you can add the package’s location to the PYTHONPATH environment variable. This will allow you to use the package with the specific version of Python required.

For example, if you have Python 3.6 installed and a package that requires Python 3.7, you can add the package’s location to the PYTHONPATH environment variable for Python 3.6. Then, when you run Python 3.6, it will be able to find and import the package.

It must be noted that this approach is not a substitute for installing packages with the correct version of Python using a package manager like pip. Instead, it is a workaround for situations where you need to use a package that is not available for the version of Python you have installed.

These examples demonstrate the flexibility of the PYTHONPATH environment variable and how it can be used to customize the search path for Python modules and packages. By setting PYTHONPATH correctly, you can avoid errors related to module imports and ensure that your Python scripts and applications can access the modules and packages they need.

Источник