Terminal tab titles that strip control characters and restore on exit.
Restoring depends on the terminal's title stack (XTWINOPS 22/23). Terminals without one keep the last title after exit.
Return whether env var name is set to a recognizably truthy value.
Unlike bool(os.environ.get(name)), this does not treat "0" or
"false" as enabled. Use this for on/off flags where the user would
reasonably expect VAR=0 to mean "disabled".
Return the command name this process was launched with.
Cached: sys.argv[0] and the launch environment are fixed for the life of
the process. Tests that vary either must call invoked_name.cache_clear().
