Issue #13609: Add two functions to query the terminal size:

os.get_terminal_size (low level) and shutil.get_terminal_size (high level).
Patch by Zbigniew Jędrzejewski-Szmek.

Lib/shutil.py

@@ -878,3 +878,46 @@ def chown(path, user=None, group=None):
             raise LookupError("no such group: {!r}".format(group))
 
     os.chown(path, _user, _group)
+
+def get_terminal_size(fallback=(80, 24)):
+    """Get the size of the terminal window.
+
+    For each of the two dimensions, the environment variable, COLUMNS
+    and LINES respectively, is checked. If the variable is defined and
+    the value is a positive integer, it is used.
+
+    When COLUMNS or LINES is not defined, which is the common case,
+    the terminal connected to sys.__stdout__ is queried
+    by invoking os.get_terminal_size.
+
+    If the terminal size cannot be successfully queried, either because
+    the system doesn't support querying, or because we are not
+    connected to a terminal, the value given in fallback parameter
+    is used. Fallback defaults to (80, 24) which is the default
+    size used by many terminal emulators.
+
+    The value returned is a named tuple of type os.terminal_size.
+    """
+    # columns, lines are the working values
+    try:
+        columns = int(os.environ['COLUMNS'])
+    except (KeyError, ValueError):
+        columns = 0
+
+    try:
+        lines = int(os.environ['LINES'])
+    except (KeyError, ValueError):
+        lines = 0
+
+    # only query if necessary
+    if columns <= 0 or lines <= 0:
+        try:
+            size = os.get_terminal_size(sys.__stdout__.fileno())
+        except (NameError, OSError):
+            size = os.terminal_size(fallback)
+        if columns <= 0:
+            columns = size.columns
+        if lines <= 0:
+            lines = size.lines
+
+    return os.terminal_size((columns, lines))