How to call a function from linux terminal

[Niloofar24]

Hi everybody. I've created a .py file with a simple function in it. Now i want to call that function from linux shell scripting. How should i do that? please help me, thank you.

[Gribouillis]

Can you post your script? It depends on what you want to do. For example, here is a function which prints hello world

#!/usr/bin/env python
# -*-coding: utf8-*-
# This is file hello.py
# Line 1 above tells the linux shell that this
# program must be executed with python. Replace
# python with python3 if needed.
# Line 2 above tells python that this file is
# encoded in utf8

# our function definition

def thefunc():
    print('hello world')

if __name__ == '__main__':
    # this block contains the code that will be executed
    # when hello.py is executed on the command line
    # It calls our function thefunc()
    thefunc()

Now save this file under the name hello.py, then in a terminal run the 2 commands

chmod +x hello.py
./hello.py

[Niloofar24]

Thank you for your answer.
Here is what i have; a file with name message.py:

def sayhi():
    print('hi everybody!')


if __name__ == "__main__":
    sayhi(int(argv[0]))

Well it's a little hard to explain what i mean....i want to type this for example python message.py sayhi on the shell and run the function.

In fact; i want to create some functions on message.py file and then call each of them separately from the terminal.

[Gribouillis]

Then the script must take an argument which is the function name. The best thing to do is to use the argparse module to parse the command line, something like

#!/usr/bin/env python3
# -*-coding: utf8-*-

def sayhi():
    print('hi everybody!')


if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(description='Execute a function')
    parser.add_argument('funcname',
        help='name of function to execute',
        metavar='FUNCNAME',
        choices=['sayhi'])
    args = parser.parse_args()
    function = globals()[args.funcname]
    function()

[sneekula]

If you saved your file as hello.py somewhere Python looks for, do this from the shell:

>>> import hello
>>> hello.thefunc()

[sneekula]

Or simpler:
>>> execfile("hello.py")

[sneekula]

Or simpler:
>>> execfile("hello.py")

You might have to give it the full file path.

[Slavi]

python file.py

[Niloofar24]

Thank you Gribouillis, i copied the code you wrote and it worked with python message.py sayhi.

Now for working with more functions what should i do?
Please look at this:

#!/usr/bin/env python3
# -*-coding: utf8-*-

def sayhi():
    print('hi everybody!')

def goodbye():
    print('see you soon!')

if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(description='Execute a function')
    parser.add_argument('funcname',
    help='name of function to execute',
    metavar='FUNCNAME',
    choices=['sayhi'])
args = parser.parse_args()
function = globals()[args.funcname]
function()


if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(description='Execute a function')
    parser.add_argument('funcname',
    help='name of function to execute',
    metavar='FUNCNAME',
    choices=['goodbye'])
args = parser.parse_args()
function = globals()[args.funcname]
function()

Here i've added an other function goodbye.
When i type python message.py sayhi and python message.py goodbye, just one of them will work. How can i call noth of them separately? How should i change the code above?
_______________
Thanks everybody for all answers :)

[Niloofar24]

Both of them*

[Slavi]

#!/usr/bin/env python3
# -*-coding: utf8-*-
def sayhi():
    print('hi everybody!')
def goodbye():
    print('see you soon!')
if __name__ == "__main__":
    sayhi()
    goodbye()

[Niloofar24]

Slavi, i copied your code, but when i type python message.py sayhi bout print messages will be displayed! 'hi everybody!' and 'see you soon' bout will be displayed to gather at the same time.

[Niloofar24]

oopss!! both*

[Slavi]

oh did u mean to be able to call them separately

[Niloofar24]

Yes. I want when i type python message.py sayhi, the function sayhi run and when type python message.py goodbye, the function goodbye run separately.

In fact; i want to have some different functions in message.py file and call them separately everytime by typing python message.py (the name of the function).

[sneekula]

I thought you want to do it from the Python shell?

[Niloofar24]

Yes! From Linux's terminal in python language.
Sorry maybe i couldn't explain good, well my English is not very good. So....let me make it clear.
I want to type this command python message.py sayhi for example, from the Linux terminal.

[sneekula]

On my Raspberry Pi computer I came up with this:

#!/usr/bin/python2
# -*- coding: utf-8 -*-
"""
Save this file as hello_arg2.py in folder
/home/pi/rpi_python

Note: line 1 has been changed to fit Debian/Rasbian Linux

Results in the Linux Python2 shell -->
>>> import sys
>>> sys.argv = ["hello_arg2.py", "sayhi"]
>>> execfile("/home/pi/rpi_python/hello_arg2.py")
Hello to you!
>>> sys.argv = ["hello_arg2.py", "saybye"]
>>> execfile("/home/pi/rpi_python/hello_arg2.py")
Hasta la vista!

note Python3 has removed execfile(), now use
>>> exec(open("/home/pi/rpi_python/hello_arg2.py").read())

"""

def sayhi():
    print("Hello to you!")

def saybye():
    print("Hasta la vista!")


if __name__ == '__main__':
    import sys
    # there is a commandline
    if len(sys.argv) > 1:
        # sys.argv[0] is the program filename
        if sys.argv[1] == "sayhi":
            sayhi()
        elif sys.argv[1] == "saybye":
            saybye()
    else:
        print("usage hello_arg2 sayhi  or  hello_arg2 saybye")

[sneekula]

    Using the LXTerminal -->
    cd rpi_python
    python hello_arg2.py sayhi
    or -->
    python hello_arg2.py saybye

[Gribouillis]

Use argparse ! It is by far the best way to do this

#!/usr/bin/env python3
# -*-coding: utf8-*-

def sayhi():
    print('hi everybody!')

def goodbye():
    print('see you soon!')

if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(description='Execute a function')
    parser.add_argument('funcname',
        help='name of function to execute',
        metavar='FUNCNAME',
        choices=['goodbye', 'sayhi']) # <-- LOOK HERE
    args = parser.parse_args()
    function = globals()[args.funcname]
    function()

[Niloofar24]

Yesssssssssss!! It works Gribouillis thank you so much :)
I've created some other functions and all of them works separately, nice!
______________
Thanks everybody for all answers.