Fix and improve demo programs

This commit does a few things that make the demos more usable.

Imports from paramiko.py3compat have been removed as that module was
removed in commit 5c4b311b (2023-01-09), making it possible to run these
demos with modern versions of the library.

GSS support was made system-conditional in all demo files, as it was
previously in demo_simple.py.

Unused imports were removed.

Docstrings were added to files that did not have them.

1 files changed, 5 insertions, 7 deletions

diff --git a/demos/demo_simple.py b/demos/demo_simple.py
index bd932c3e..1550e1bc 100644..100755
--- a/demos/demo_simple.py
+++ b/demos/demo_simple.py
@@ -18,14 +18,14 @@
 # along with Paramiko; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.
 
+"""
+Demonstrates how to open a shell at an SSH server, using basic password
+authentication or GSSAPI.
+"""
 
-import base64
 import getpass
-import os
-import socket
 import sys
 import traceback
-from paramiko.py3compat import input
 
 import paramiko
 
@@ -44,8 +44,6 @@ UseGSSAPI = (
 DoGSSAPIKeyExchange = (
     paramiko.GSS_AUTH_AVAILABLE
 )  # enable "gssapi-kex" key exchange, if supported by your python installation
-# UseGSSAPI = False
-# DoGSSAPIKeyExchange = False
 port = 22
 
 # get hostname
@@ -93,7 +91,7 @@ try:
                 gss_kex=DoGSSAPIKeyExchange,
             )
         except Exception:
-            # traceback.print_exc()
+            traceback.print_exc()
             password = getpass.getpass(
                 "Password for %s@%s: " % (username, hostname)
             )