Hi Jason, On Thu, Jul 4, 2024 at 5:31 PM Jason McIntyre <j...@kerhand.co.uk> wrote: > > On Thu, Jul 04, 2024 at 12:01:55AM +0100, Jason McIntyre wrote: > > On Wed, Jul 03, 2024 at 10:08:09PM +0100, Stuart Henderson wrote: > > > > > > > > A random value (within the legal range) may be obtained by using > > > > the ???~??? > > > > character in a field. The interval of the random value may be > > > > specified > > > > explicitly, for example ???0~30??? will result in a random value > > > > between 0 > > > > and 30 inclusive. If either (or both) of the numbers on either > > > > side of > > > > the ???~??? are omitted, the appropriate limit (low or high) for > > > > the field > > > > will be used. The '~' character gets expanded to a random value > > > > only once, at table install time. > > > > > > "only once, at table install time" doesn't seem quite clear to me. > > > In particular consider "only once" when you edit the crontab once, > > > then edit it again. > > > > > > How about this? > > > > > > The '~' character gets expanded to a random value when the > > > .Nm crontab > > > is loaded. > > > > > > > well, we already say "A random value ... may be obtained", which i > > think is equivalent (note the singular). and this text does not > > explicitly say that it remains at this value afterwards, which is what > > we are supposed to be addressing. > > > > i still don;t think the complexity of the text is warranted. it works > > how it works. will someone stop using "random" because of this, or > > somehow be caught out (genuinely asking)? > > > > i'm not trying to reject the suggestion. i just think that being > > explicit will add a level of complexity that won;t be an improvement. i > > did try to rework the text! for example: > > > > A random, fixed, value... > > > > it's still not explicit ;( > > > > Once loaded, this value remains constant. > > > > don;t know... > > > > jmc > > > > > "The allowed values for the fields" above misses the various > > > possibilities involving ~ too. > > > > > so a diff to try and address sthen and deraadt's points. i've tried to > be more explicit about the random value. > > ... > > Fields are separated by blanks or tabs. The command may be one or more > fields long. The allowed values for the fields are: > > field allowed values > minute *, ~, or 0-59 > hour *, ~, or 0-23 > day-of-month *, ~, or 1-31 > month *, ~, 1-12, or a name (see below) > day-of-week *, ~, 0-7, or a name (0 or 7 is Sunday) > user a valid username > [flags] runtime flags, denoted with '-' > command text > > ... > > A random value for a field may be obtained using the `~' character. A > value is generated every time the tab is loaded. On its own, it denotes > a random value appropriate for the field. It can also be used in a range > to make the interval more specific. If either of the numbers in a range > are omitted, the appropriate limit (low or high) for that field will be > used. For example, both "0~30" and "~30" in the minute field would > result in a random value between 0 and 30.
I think it is much clear now, specially the "every time the tab is loaded" part. Adding "~" to the allowed values was also good, in my opinion. Thanks for your work! Best, --Kor > > > Index: crontab.5 > =================================================================== > RCS file: /cvs/src/usr.sbin/cron/crontab.5,v > diff -u -p -r1.42 crontab.5 > --- crontab.5 6 May 2023 23:06:27 -0000 1.42 > +++ crontab.5 4 Jul 2024 16:55:56 -0000 > @@ -122,11 +122,11 @@ The command may be one or more fields lo > The allowed values for the fields are: > .Bl -column "day-of-month" "allowed values" -offset indent > .It Sy field Ta Sy allowed values > -.It Ar minute Ta * or 0\(en59 > -.It Ar hour Ta * or 0\(en23 > -.It Ar day-of-month Ta * or 1\(en31 > -.It Ar month Ta * or 1\(en12 or a name (see below) > -.It Ar day-of-week Ta * or 0\(en7 or a name (0 or 7 is Sunday) > +.It Ar minute Ta *, ~, or 0\(en59 > +.It Ar hour Ta *, ~, or 0\(en23 > +.It Ar day-of-month Ta *, ~, or 1\(en31 > +.It Ar month Ta *, ~, 1\(en12, or a name (see below) > +.It Ar day-of-week Ta *, ~, 0\(en7, or a name (0 or 7 is Sunday) > .It Ar user Ta a valid username > .It Op Ar flags Ta runtime flags, denoted with '-' > .It Ar command Ta text > @@ -147,15 +147,22 @@ For example, > .Ar hour > entry specifies execution at hours 8, 9, 10 and 11. > .Pp > -A random value (within the legal range) may be obtained by using the > +A random value for a field may be obtained using the > .Ql ~ > -character in a field. > -The interval of the random value may be specified explicitly, for example > +character. > +A value is generated every time the tab is loaded. > +On its own, > +it denotes a random value appropriate for the field. > +It can also be used in a range to make the interval more specific. > +If either of the numbers in a range are omitted, > +the appropriate limit (low or high) for that field will be used. > +For example, both > .Dq 0~30 > -will result in a random value between 0 and 30 inclusive. > -If either (or both) of the numbers on either side of the > -.Ql ~ > -are omitted, the appropriate limit (low or high) for the field will be used. > +and > +.Dq ~30 > +in the > +.Ar minute > +field would result in a random value between 0 and 30. > .Pp > Step values can be used in conjunction with ranges. > Following a range with >
