How to run a python script external to Blender to run bpy commands in Blender'spython console

This is the equivalent to running the script directly, referencing a scripts path from a 2 line text-block.

filename = "/full/path/to/myscript.py"
exec(compile(open(filename).read(), filename, 'exec'))

You might want to reference a script relative to the blend file.

import bpy
filepath = bpy.path.abspath("//myscript.py")
exec(compile(open(filepath).read(), filepath, 'exec'))

Using blender's text editor you can open a script file to read and edit it. The text editor also has a "Run Script" button to easily run the script you are editing.

An open text file can also be run within the python console with

exec(compile(bpy.data.texts['Text'].as_string(), 'textblock', 'exec'))

this has an advantage when debugging as the variables in the script will remain available in the console after it has been run.

Some time back I started using an addon posted on blender artists that adds a menu to the console which lets you run any open text block in blender's python console. You gave me an idea to expand it a bit by adding another menu made from script files in a directory, the addon will now also list the files within a specific directory which will be loaded and run when chosen. You can download the updated addon here.

Here are two variations on the answers given by Patan and sambler that some may prefer.

Variant of Sambler's answer

If you care about in-Python-console logging, but not availability/persistence of variables, then this approach is a slightly simpler alternative to sambler's answer: (run this in the Python console)

bpy.data.texts["NameOfScript"].as_module()

Variant of Patam's answer

If you care about in-Python-console logging, but not availability/persistence of variables, then this approach is an alternative to Patam's answer: (use this as your in-Blender "launcher" script)

import sys
import bpy

# this code block will redirect calls to print() to show up in the Python-console panel
class StdOutOverride:
    def write(self, text):
        sys.__stdout__.write(text) # also send to standard-output (can comment this out)
        if text != '\n': # ignore extra stdout.write('\n') call at end of each print()
            for line in text.replace('\t', '    ').split('\n'):
                for area in bpy.context.screen.areas:
                    if area.type == 'CONSOLE':
                        with bpy.context.temp_override(area=area):
                            bpy.ops.console.scrollback_append(text=line, type='OUTPUT')
sys.stdout = StdOutOverride()

filename = "/full/path/to/myscript.py"
exec(compile(open(filename).read(), filename, 'exec'))

I prefer this last approach myself, as it lets you get logging in the Python console, while still being able to use the convenient "Play" button in the script-panel's toolbar. (and this way there's less conflict, in case variable-names in the script overlap with whatever code I may be iterating on in the Python console)