Get the terminal window size. Not in a bullshit ENV dependent manor.

term_size.rb

# From the tty_ioctl man page in Linux.
#
# TIOCGWINSZ     struct winsize *argp
#        Get window size.
#
# TIOCSWINSZ     const struct winsize *argp
#        Set window size.
#
# The struct used by these ioctls is defined as
#
#     struct winsize {
#         unsigned short ws_row;
#         unsigned short ws_col;
#         unsigned short ws_xpixel;   /* unused */
#         unsigned short ws_ypixel;   /* unused */
#     };
#         rows cols width height

window = [ 0, 0, 0, 0 ].pack('SSSS')
fd = IO.sysopen("/dev/tty", "w")
terminal = IO.new(fd, "w")
terminal.ioctl(0x5413, window) # defined in asm-generic/ioctls.h
rows, cols, width, height = window.unpack('SSSS')

puts "Rows: #{rows}, Cols: #{cols}, Width: #{width}, Height: #{height}"