How to find python installation directory on Ubuntu

Question

I have just migrated from Windows environment. I have installed Python 3.2 in a separate directory. How can I get the python installation path in Ubuntu shell?

Is there any way I can let the shell know/choose at runtime which python version is to be used for further code execution?

Are there any environment variables and search path kind of things in Ubuntu Linux as well?

Solution 1

First question:

which python though its usually /usr/bin/python for the 2.7

Second question:

From a terminal & python2.7: python2.7 yourfile.py.
Simailarly for 3.2: python3.2 yourfile.py though 3.2 isn't installed by default. (You can apt-get install python3.2.)

What python yourfile.py will do depends on which alternative is used for your python interpreter. You can change that by issuing update-alternatives python as root (or by using su).

Third question:

Environment variables are shell dependent, though you can write them out with echo $variable and set them with variable=value (from bash). The search path is simply called PATH and you can get yours by typing echo $PATH.

I hope this was helpful.

Solution 2

If you want to find the location of a program you can just use whereis <program>.

In your case run:

whereis python2.7
whereis python3.2

For finding every file that apt-get has copied for installation use:

dpkg -S python2.7
dpkg -S python3.2

But maby it is recommend to save it in a textfile, because the output is to large.

dpkg -S python2.7 >log.txt
gedit log.txt

for running .py file with python 3.2

python3.2 <file.py>

Solution 3

Here is a simple way, run in terminal:

type -a python

or

type -a python3

Solution 4

For Python2.7

whereis python2.7 

For Python3.2

whereis python3.2

For Python 3.8

which python3

or

whereis python3

View more solutions

Comments

[avimehenwal]

Thanks @Wolfer ! Answer was indeed helpful and much appreciated. If somebody like me has changed default python 3 installation path then .. ? How can I check path and run using this version ?

[avimehenwal]

Also, I am not getting any output for $echo $variable

[avimehenwal]

Thanks @Thomas ! This command 'whereis python2.7' is displaying many paths, but I think there has to be single python installation directory !

[Thomas15v]

dpkg -S python2.7 shows all the files of python2.7. "/usr/lib/python2.7" is the directory of python2.7.

[avimehenwal]

I m a bit confused, /usr/bin/python is the default shebang we use while python package is located at /usr/lib/python2.7 ? Is that true ??

[Wolfer]

which python2.7 and which python3.2 will return each interpreter's install path (or return nothing if it's not installed).

[Ravexina]

Doesn't really add anything to the other answers...

[Admin]

@Ravexina Python 3.8 and made it little simple.

[avimehenwal]

This is a great answer. Old schooled bash to the rescue :D Thankyou for sharing

[Danny Bullis]

A little bit of detail about what the type command is and what it does, particularly with the -a argument, would be helpful.