import os
# you can do like this
columns, lines = os.get_terminal_size()
# or
size = os.get_terminal_size()
columns = size.columns
lines = size.lines
If you install xdotool, you can change the size of the terminal window with something like this:
import subprocess
import shlex
id_cmd='xdotool getactivewindow'
resize_cmd='xdotool windowsize --usehints {id} 100 30'
proc=subprocess.Popen(shlex.split(id_cmd),stdout=subprocess.PIPE)
windowid,err=proc.communicate()
proc=subprocess.Popen(shlex.split(resize_cmd.format(id=windowid)))
proc.communicate()