Incrementing time (minutes and seconds) in bash / shell script

Answer 1

You could use epoch time - i.e., seconds since 1 Jan 1970 00:00:00, for example:

#!/bin/bash

time=0
echo `date -d "1970-01-01 00:00:00 UTC $time seconds" +"%H:%M:%S"`
time=$((time + 600))
echo `date -d "1970-01-01 00:00:00 UTC $time seconds" +"%H:%M:%S"`
time=$((time + 600))
echo `date -d "1970-01-01 00:00:00 UTC $time seconds" +"%H:%M:%S"`

gives this output:

$ /tmp/datetest.sh
00:00:00
00:10:00
00:20:00
$