detect if sys.stdin is ...

[ljmetzger]

The following was tested on Python 3.6.5 using Windows 10 in the United States:

# Tested using Python 3.6.5 on Windows 10 in the United States
#
# Reference: https://python-forum.io/Thread-detect-if-sys-stdin-is

import sys

if sys.stdin.isatty():
    print ("Do Nothing - stdin is either 'tty' or 'null device'.")
else:
    print ("Process 'stdin' from 'pipe' or from 'file redirection'.")
    for i, dataline in enumerate(sys.stdin, start=1):
        print(i, dataline)

The following Windows cmd.exe script was used to test the code (e.g. file abc.bat):
NOTE: The follow is NOT Python code but a Windows .bat file

@echo off

echo Testing stdin           >ScratchStdOut.txt 
echo.                       >>ScratchStdOut.txt 

echo ######################   >>ScratchStdOut.txt 
echo Testing 'Keyboard' stdin >>ScratchStdOut.txt 
python redirectStdin-002.py   >>ScratchStdOut.txt 


echo ######################      >>ScratchStdOut.txt 
echo Testing 'Null Device' stdin >>ScratchStdOut.txt 
python redirectStdin-002.py      >>ScratchStdOut.txt  <nul


echo ###################### >>ScratchStdOut.txt 
rem NOTE: Windows prevents this from running if the redirected 'stdin' file DOES NOT EXIST
rem This creates and deletes file 'Scratch00.txt'
echo Testing 'Redirected' File stdin >>ScratchStdOut.txt 
echo Hello >Scratch00.txt
echo World >>Scratch00.txt
python redirectStdin-002.py >>ScratchStdOut.txt  <Scratch00.txt 
if exist Scratch00.txt del Scratch00.txt

echo ###################### >>ScratchStdOut.txt 
echo Testing 'Pipe' stdin   >>ScratchStdOut.txt 
echo Pipe stdin text - Hello World | python redirectStdin-002.py >>ScratchStdOut.txt  


echo ###################### >>ScratchStdOut.txt 

type ScratchStdOut.txt 
pause
exit

Results using the .bat file:

Output:
Testing stdin

######################
Testing 'Keyboard' stdin
Do Nothing - stdin is either 'tty' or 'null device'.
######################
Testing 'Null Device' stdin
Do Nothing - stdin is either 'tty' or 'null device'.
######################
Testing 'Redirected' File stdin
Process 'stdin' from 'pipe' or from 'file redirection'.
1 Hello

2 World

######################
Testing 'Pipe' stdin
Process 'stdin' from 'pipe' or from 'file redirection'.
1 Pipe stdin text - Hello World

######################

See the .zip file attachment containing:
a. RedirectStdin-002.bat
b. RedirectStdin-002.py

Lewis