Simple way to convert HH:MM:SS (hours:minutes:seconds.split seconds) to seconds

Question

What\'s an easy way to convert 00:20:40.28 (HH:MM:SS) to seconds with a Bash script?

Split seconds can be cut out, it’s not essential.

Answer 1

echo "40.25" | awk -F: '{ if (NF == 1) {print $NF} else if (NF == 2) {print $1 * 60 + $2} else if (NF==3) {print $1 * 3600 + $2 * 60 + $3} }'
40.25
echo "10:40.25" | awk -F: '{ if (NF == 1) {print $NF} else if (NF == 2) {print $1 * 60 + $2} else if (NF==3) {print $1 * 3600 + $2 * 60 + $3} }'
640.25
echo "20:10:40.25" | awk -F: '{ if (NF == 1) {print $NF} else if (NF == 2) {print $1 * 60 + $2} else if (NF==3) {print $1 * 3600 + $2 * 60 + $3} }'
72640.25