python interative mode does not work when reading from std in

Question

Given the following python script....

$ cat readStdin.py 
#!/usr/bin/python

import sys

var = "".join(sys.stdin.readlines()).rstrip()
print var

... I get the follwing output:

$ echo hello  | python -i readStdin.py 
hello
>>> 
$

... in other words it does not hang in the python console, but goes back to bash. Does anyone out there know how to make it stay in the python console???

This isn't an artifact of `python -i` not working (it works fine). If you run your script without the shell pipeline it goes OK. The problem is that the python tries to read more data from `echo` but that data doesn't exist, so it gets `EOF` immediately and closes (as I understand it). Good question though ... — mgilson, Oct 09 '12 at 15:34

Abhishek Mishra · Accepted Answer · 2012-10-10T02:18:46.400

Consider this -

$ echo print  4*2 | python -i
Python 2.7.2 (default, Jun 20 2012, 16:23:33) 
Type "help", "copyright", "credits" or "license" for more information.
>>> 8
>>> 
$

Echo produces print 4*2. Python even in interactive mode, considers this as input to be interpreted. Hence we see the 8 there. After this, the interpreter encounters an EOF, so it quits. Consider what you press to quit the interpreter - Ctrl+d or ^D. This is just another way to produce EOF on *nix.

python interative mode does not work when reading from std in

1 Answers1