For more information see Terminal window commands, Discover tput and Apple Shell Scripting Primer -> ANSI Escape Sequence Tables.

tput lines
tput cols

echo $LINES
echo $COLUMNS

stty size
stty size | awk '{print $1}'    # lines
stty size | awk '{print $NF}'   # columns

stty size | cut -d" " -f1   # lines
stty size | cut -d" " -f2   # columns 

stty -a | awk '/rows/ {print $4}'      # lines
stty -a | awk '/columns/ {print $6}'   # columns

stty -a | sed -E -n -e 's/^.*[^[:digit:]]([[:digit:]]+)[[:space:]]+rows;.*$/\1/p;q;'
stty -a | sed -E -n -e 's/^.*[^[:digit:]]([[:digit:]]+)[[:space:]]+columns;.*$/\1/p;q;'



# automatically resize the Terminal window if it gets smaller than the default size

# positive integer test (including zero)
function positive_int() { return $(test "$@" -eq "$@" > /dev/null 2>&1 && test "$@" -ge 0 > /dev/null 2>&1); }


# resize the Terminal window
function sizetw() { 
   if [[ $# -eq 2 ]] && $(positive_int "$1") && $(positive_int "$2"); then 
      printf "\e[8;${1};${2};t"
      return 0
   fi
   return 1
}


# the default Terminal window size: 26 lines and 107 columns
sizetw 26 107


# automatically adjust Terminal window size
function defaultwindow() {

   DEFAULTLINES=26
   DEFAULTCOLUMNS=107

   if [[ $(/usr/bin/tput lines) -lt $DEFAULTLINES ]] && [[ $(/usr/bin/tput cols) -lt $DEFAULTCOLUMNS ]]; then
      sizetw $DEFAULTLINES $DEFAULTCOLUMNS
   elif [[ $(/usr/bin/tput lines) -lt $DEFAULTLINES ]]; then
      sizetw $DEFAULTLINES $(/usr/bin/tput cols)
   elif [[ $(/usr/bin/tput cols) -lt $DEFAULTCOLUMNS ]]; then
      sizetw $(/usr/bin/tput lines) $DEFAULTCOLUMNS
   fi

   return 0
}


# SIGWINCH is the window change signal
trap defaultwindow SIGWINCH    


sizetw 26 70
sizetw 10 107
sizetw 4 15