Re: Is there a POSIX compliant way of turning a "HH:MM:SS" formatted string to seconds? ...

[Greg Wooledge <greg@wooledge.org>]

On Fri, Jul 18, 2025 at 18:59:06 -0700, Michael Paoli wrote:
> echo $(( $(echo 07:08:09 | sed -e 's/^0*\([0-9]\)/3600 * \1 +
> /;s/:0*\([0-9]:\)/60 * \1/;s/:0*\([0-9]\)$/ + \1/;') ))

This one is missing some * operators.  You're only capturing a single
digit in each segment, but there could be two digits (or maybe even
more in the first segment).

hobbit:~$ echo $(( $(echo 07:18:19 | sed -e 's/^0*\([0-9]\)/3600 * \1 + /;s/:0*\([0-9]:\)/60 * \1/;s/:0*\([0-9]\)$/ + \1/;') ))
bash: 3600 * 7 + :18:19 : syntax error: operand expected (error token is ":18:19 ")

Realistically, though, why are people so *bent* on writing "one-liners"?
It's less efficient and less readable than the straightforward code.

Longer code is not worse.  It's often better.