if STREAM.isatty():

[Hongyi Zhao]

On Fri, 30 Aug 2019 01:29:48 +0200, Peter Otten wrote:

> Perhaps a simple example can help?
> 
> $ cat checktty.py import sys
> 
> stream = sys.stdout
> 
> if stream.isatty():
>     message = "tty"
> else:
>     message = "no tty"
> print(message, file=stream)
> 
> When you run the script it prints to the terminal:
> 
> $ python3 checktty.py tty
> 
> But when you redirect to a pipe or into a file:
> 
> $ python3 checktty.py | cat no tty
> 
> $ python3 checktty.py > tmp.txt $ cat tmp.txt no tty


But, see my example:

$ cat check-isatty.py 
import sys
import time

if sys.stderr.isatty():
	p = 'tty ' + '\r'
else:
	p = 'no tty ' + '\n'

sys.stderr.write(p)
sys.stderr.flush()
time.sleep(1.0)


I run both of the following commands:

$ python check-isatty.py
$ python check-isatty.py | cat

Both will output `tty'.  So still I cannot figure out the issue.

Regards