From: Stuart Henderson <stu@spacehopper.org>
Subject: Re: ts(1) - ISO8601 as default format
To: Job Snijders <job@bsd.nl>
Cc: tech@openbsd.org
Date: Mon, 2 Nov 2026 15:01:00 +0000

On 2026/11/02 14:50, Job Snijders wrote:
> On Mon, Nov 02, 2026 at 02:38:43PM +0100, Christian Schulte wrote:
> > Do not use 'Z'. Use '%z'.
> 
> Sure... but let's save some space in case it is +0000. Maybe like so?
> 
> This changes the ts(1) default format to ISO8601.
> 
> Index: ts.1
> ===================================================================
> RCS file: /cvs/src/usr.bin/ts/ts.1,v
> diff -u -p -r1.8 ts.1
> --- ts.1	3 Jul 2022 16:55:39 -0000	1.8
> +++ ts.1	2 Nov 2026 14:48:34 -0000
> @@ -52,7 +52,7 @@ specifications described in the
>  .Xr strftime 3
>  manual page.
>  The default format is
> -.Qq %b %d %H:%M:%S ;
> +.Qq %Y-%m-%dT%H:%M:%S%z ;
>  or
>  .Qq %H:%M:%S
>  if one of the
> @@ -79,9 +79,9 @@ and
>  .Qq 4:20:00.00001 .
>  .Sh EXAMPLES
>  .Bd -literal -offset indent
> -$ (echo foo; sleep 2; echo bar) | ts
> -Jun 28 12:13:38 foo
> -Jun 28 12:13:40 bar
> +$ (echo foo; sleep 2; echo bar) | TZ=Etc/UTC ts
> +2026-11-02T14:24:50Z foo
> +2026-11-02T14:24:52Z bar
>  
>  $ ls | ts -i %.S
>  00.000452 CVS
> Index: ts.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/ts/ts.c,v
> diff -u -p -r1.11 ts.c
> --- ts.c	11 Oct 2022 07:36:27 -0000	1.11
> +++ ts.c	2 Nov 2026 14:48:34 -0000
> @@ -34,7 +34,7 @@ struct usec {
>  	char *pos;
>  };
>  
> -static char		*format = "%b %d %H:%M:%S";
> +static char		*format;
>  static char		*buf;
>  static char		*outbuf;
>  static size_t		 bufsize;
> @@ -44,6 +44,17 @@ static void		 fmtfmt(void);
>  static void		 fmtprint(const struct timespec *);
>  static void __dead	 usage(void);
>  
> +static int
> +localtz_is_utc(void)
> +{
> +	time_t now;
> +	struct tm *local;
> +
> +	now = time(NULL);
> +	local = localtime(&now);
> +	return local->tm_gmtoff == 0;
> +}
> +
>  int
>  main(int argc, char *argv[])
>  {
> @@ -87,6 +98,12 @@ main(int argc, char *argv[])
>  
>  	if (argc == 1)
>  		format = *argv;
> +	else {
> +		if (localtz_is_utc())
> +			format = "%Y-%m-%dT%H:%M:%SZ";
> +		else
> +			format = "%Y-%m-%dT%H:%M:%S%z";
> +	}
>  
>  	bufsize = strlen(format) + 1;
>  	if (bufsize > SIZE_MAX / 10)
> 

that messes up the formatting if run across a DST change in +0000/+0100
timezones (Europe/Dublin, Europe/Jersey, Europe/London, etc).