How to execute a file within the Python interpreter?

Several ways.

From the shell
```
python someFile.py
```
From inside IDLE, hit F5.
If youre typing interactively, try this (Python3):
```
>>> exec(open(filename.py).read())
```

For Python 2:

>>> variables= {}
>>> execfile( someFile.py, variables )
>>> print variables # globals from the someFile module

For Python 2:

>>> execfile(filename.py)

For Python 3:

>>> exec(open(filename.py).read())
# or
>>> from pathlib import Path
>>> exec(Path(filename.py).read_text())

See the documentation. If you are using Python 3.0, see this question.

See answer by @S.Lott for an example of how you access globals from filename.py after executing it.

Python 2 + Python 3

exec(open(./path/to/script.py).read(), globals())

This will execute a script and put all its global variables in the interpreters global scope (the normal behavior in most scripting environments).