bash function to convert [[hh:]mm:]ss[.ms] timecode to seconds

toSeconds.sh

#!/bin/bash -eu
# toSeconds "1:00.25"
# "60.25"
# toSeconds "1:00:00.25"
# "3600.25"
toSeconds() { 
    echo $1 | awk -F: 'NF==3 { print ($1 * 3600) + ($2 * 60) + $3 } NF==2 { print ($1 * 60) + $2 } NF==1 { print 0 + $1 }'
}