how to center script output in the middle of the screen?

Question

Here i have a binary clock which outputs binary clock in 16 different colors and i am trying to make it appear in center of the screen but cant do it. If you have any suggestions how to do it then please let me know. thanks

color=("0;30" "0;31" "0;32" "0;33" "0;34" "0;35" "0;36" "0;37" "1;30" "1;31" "1;32" "1;33" "1;34" "1;35" "1;36" "1;37")
color2=${#color[*]}
while true;
do
clear
echo -ne '\e['${color[$((RANDOM%color2))]}m
hour=$(date +%H)
minute=$(date +%M)
second=$(date +%S)
hour_binary=$(echo "ibase=10;obase=2;$hour" | bc)
minute_binary=$(echo "ibase=10;obase=2;$minute" | bc)
second_binary=$(echo "ibase=10;obase=2;$second" | bc)
printf "%06d\n" "$hour_binary"
printf "%06d\n" "$minute_binary"
printf "%06d" "$second_binary"
sleep 1
done

Answer 1

If you are referring to the center of the terminal window, get the columns and rows of the terminal window with:

COLS=$(tput cols)
ROWS=$(tput lines)
CLOCKWIDTH=8       # Assuming a HH:MM:SS format
CENTERCOL=$((COLS/2))
CENTERCOL=$((CENTERCOL-CLOCKWIDTH))
CENTERROW=$((ROWS/2))

And then use the tput command to set the cursor position with:

tput cup $CENTERCOL $CENTERROW

See http://www.cyberciti.biz/tips/spice-up-your-unix-linux-shell-scripts.html for an example using tput and https://www.gnu.org/software/termutils/manual/termutils-2.0/html_chapter/tput_1.html for more information about the tput command.

Answer 2

What I would do :

cols=$(tput cols)
lines=$(tput lines)
numcols=$(((cols-6)/2))
numlines=$((lines/2))

while true; do
    clear
    tput setaf $((RANDOM%8))
    hour=$(date +%H)
    minute=$(date +%M)
    second=$(date +%S)
    hour_binary=$(echo "ibase=10;obase=2;$hour" | bc)
    minute_binary=$(echo "ibase=10;obase=2;$minute" | bc)
    second_binary=$(echo "ibase=10;obase=2;$second" | bc)
    tput cup $numlines $numcols
    printf "%06d\n" "$hour_binary"
    tput cup $((numlines+1)) $numcols
    printf "%06d\n" "$minute_binary"
    tput cup $((numlines+2)) $numcols
    printf "%06d" "$second_binary"
    tput cup $((numlines+3)) $numcols
    sleep 1
done

I have replaced hard coded ansi sequences by using tput for the colors too