piping from stdin to a python code in a bash script

I have a bash script, f, that contains python code. That python code reads from standard input. I want to be able to call my bash script as follows:

f input.txt > output.txt

In the example above, the python code will read from input.txt and will write to output.txt.

I’m not sure how to do this. I know that if I wanted to just write to a file, then my bash script would look like this

#!/bin/bash
python << EOPYTHON > output.txt
#python code goes here
EOPYTHON

I tried changing the second line in the code above to the following, but without luck

python << EOPYTHON $*

I’m not sure how else to go about doing this. Any suggestions?

EDIT I’ll give a more concrete example. Consider the following bash script, f

#!/bin/bash
python << EOPYTHON 
import sys
import fileinput
for i in fileinput.input():
    sys.stdout.write(i + 'n')
EOPYTHON

I want to run my code with the following command

f input.txt > output.txt

How do I change my bash script so that it uses “input.txt” as the input stream?

Answer

Updated Answer

If you absolutely must run the way you ask, you could do something like this:

#!/bin/bash
python -c 'import os
for i in range(3):
   for j in range(3):
     print(i + j)
'  < "$1"

Original Answer

Save your python code in a file called script.py and change your script f to this:

#!/bin/bash
python script.py < "$1"