Klist python subprocess return

Question

I need some help to understand the windows cmd/ps behavior and how to handle it on python.

If I run "klist" on a command prompt (CMD) or PowerShell (PS) on any folder, I get this response:

C:\>klist
A Identificação de Logon atual é 0:0x249a0c1
Tíquetes em Cache: (0)

If I run klist under the MIT folder (C:\Program Files\MIT\Kerberos\bin), I have this response (the response I am expecting in any scenario)

C:\Program Files\MIT\Kerberos\bin>klist
Ticket cache: FILE:C:\Users\XXX\XXXXX\krb5\KRB5CCNAME
Default principal: XXXXX@XXXX.COM.BR

Valid starting     Expires            Service principal
08/02/22 22:38:34  08/03/22 19:53:30  krbtgt/XXX.COM.BR@XXX.COM.BR
        renew until 08/03/22 22:38:34

If I run klist in PS at MIT folder, I got a totally different response:

PS C:\Program Files\MIT\Kerberos\bin> klist
A Identificação de Logon atual é 0:0x249a112
Tíquetes em Cache: (0)

At first : Why does CMD and PS behave diffently on running the klist executable at MIT folder?

At Second : How do I set my windows "default" klist to MIT klist (instead of the other that I don´t even know about)?

I have a Python scrip that runs a python subprocess run on "klist" to get status of an active(or not) ticket. Due to the issue showed above, as it "run" the klist, they get wrong answers.

# checa se há tickets e se estão expirados
klist = sp.run(["klist", "-s"], timeout=5, encoding="iso8859-1")
if klist.returncode == 1:
    return False

# checa se os tickets existentes pertencem ao usuário e ao cluster correto
klist = sp.run(
    ["klist"], stdout=sp.PIPE, stderr=sp.PIPE, encoding="iso8859-1", timeout=5
)
if klist.returncode == 1:
    return False

At Third : How do I set my python scrip above to run the "right" klist (supposing that I couldn't change windows default behavior)?

Answer 1

At first: Why does CMD and PS behave diffently on running the klist executable at MIT folder?

CMD, traditionally for Windows (and MS-DOS), looks for a klist.exe in the current directory first – therefore it runs C:\Program Files\MIT\Kerberos\bin\klist.exe when you're in that directory.

PowerShell does not do this – it only looks in $env:PATH , unless it was explicitly given a full path to run. Similarly to what you'd do in Unix shells such as Bash, only .\klist would run klist.exe in the current directory, while a bare klist is only checked against locations in PATH (ignoring the current directoy).

At Second: How do I set my windows "default" klist to MIT klist (instead of the other that I don´t even know about)?

Edit your Windows %PATH% environment variable to put the MIT Kerberos 'bin' directory at the beginning.

At Third: How do I set my python scrip above to run the "right" klist (supposing that I couldn't change windows default behavior)?

Either specify the full path to the.exe file:

sp.run([r"C:/Program Files/MIT/Kerberos/bin/klist", "-s"], ...)

or update PATH for that process only:

os.environ["PATH"] = r"C:\Program Files\MIT\Kerberos\bin;" + os.environ["PATH"]