Issue #23983: Update the pty module example.

Changes:

* Fixed a ResourceWarning warning
* Used argparse instead of getopt

Doc/library/pty.rst

@@ -58,40 +58,32 @@ The following program acts like the Unix command :manpage:`script(1)`, using a
 pseudo-terminal to record all input and output of a terminal session in a
 "typescript". ::
 
-   import sys, os, time, getopt
-   import pty
-
-   mode = 'wb'
-   shell = 'sh'
-   filename = 'typescript'
-   if 'SHELL' in os.environ:
-       shell = os.environ['SHELL']
-
-   try:
-       opts, args = getopt.getopt(sys.argv[1:], 'ap')
-   except getopt.error as msg:
-       print('%s: %s' % (sys.argv[0], msg))
-       sys.exit(2)
-
-   for opt, arg in opts:
-       # option -a: append to typescript file
-       if opt == '-a':
-           mode = 'ab'
-       # option -p: use a Python shell as the terminal command
-       elif opt == '-p':
-           shell = sys.executable
-   if args:
-       filename = args[0]
-
-   script = open(filename, mode)
-
-   def read(fd):
-       data = os.read(fd, 1024)
-       script.write(data)
-       return data
-
-   sys.stdout.write('Script started, file is %s\n' % filename)
-   script.write(('Script started on %s\n' % time.asctime()).encode())
-   pty.spawn(shell, read)
-   script.write(('Script done on %s\n' % time.asctime()).encode())
-   sys.stdout.write('Script done, file is %s\n' % filename)
+    import argparse
+    import os
+    import pty
+    import sys
+    import time
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-a', dest='append', action='store_true')
+    parser.add_argument('-p', dest='use_python', action='store_true')
+    parser.add_argument('filename', nargs='?', default='typescript')
+    options = parser.parse_args()
+
+    shell = sys.executable if options.use_python else os.environ.get('SHELL', 'sh')
+    filename = options.filename
+    mode = 'ab' if options.append else 'wb'
+
+    with open(filename, mode) as script:
+        def read(fd):
+            data = os.read(fd, 1024)
+            script.write(data)
+            return data
+
+        print('Script started, file is', filename)
+        script.write(('Script started on %s\n' % time.asctime()).encode())
+
+        pty.spawn(shell, read)
+
+        script.write(('Script done on %s\n' % time.asctime()).encode())
+        print('Script done, file is', filename)