[Tutor] Please correct my error handling

[Robert Alexander]

Thank you guys.

So as you pointed out I was catching the error at the wrong place.

Following is the corrected code. I’ll also investigate the easier
alternatives you proposed later on.

Take care

import subprocess

# first try a legit (*nix) command
process = subprocess.Popen(
    ["/bin/ls", "-l"], stdout=subprocess.PIPE, stderr=subprocess.PIPE
)
stdout, stderr = process.communicate()
if not stderr:
    print("--No errors--\n", stdout.decode())
else:
    print("--Error found--\n", stderr.decode())

# now repeat with an illegal option
process = subprocess.Popen(
    ["/bin/ls", "-I"], stdout=subprocess.PIPE, stderr=subprocess.PIPE
)
stdout, stderr = process.communicate()
if not stderr:
    print("--No errors--\n", stdout.decode())
else:
    print("--Error found--\n", stderr.decode())

# now repeat with an inexisting command
# and catch the Popen error this time
try:
    process = subprocess.Popen(
        ["/bin/lsd", "-I"], stdout=subprocess.PIPE, stderr=subprocess.PIPE
    )
except FileNotFoundError:
    print("Command not found. Did you install it?")
else:
    stdout, stderr = process.communicate()
    if not stderr:
        print("--No errors--\n", stdout.decode())
    else:
        print("--Error found--\n", stderr.decode())