From 5990bfb40b4e21496de7ebced1fad69c4a80268d Mon Sep 17 00:00:00 2001 From: Brian Somers Date: Fri, 4 Jun 2010 06:56:58 +0000 Subject: [PATCH] Explain that setting an absolute day value can fail and that the month should usually be set first when using -v. Adjust an example that sets the day to 30 before setting the month to 3 in accordance with this approach as the example would always fail in February! PR: 147354 MFC after: 2 weeks --- bin/date/date.1 | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/bin/date/date.1 b/bin/date/date.1 index 496f197ccf5..d1cbb445710 100644 --- a/bin/date/date.1 +++ b/bin/date/date.1 @@ -32,7 +32,7 @@ .\" @(#)date.1 8.3 (Berkeley) 4/28/95 .\" $FreeBSD$ .\" -.Dd June 2, 2007 +.Dd June 3, 2010 .Dt DATE 1 .Os .Sh NAME @@ -219,6 +219,14 @@ When the date is adjusted to a specific value that occurs twice the resulting timezone will be set so that the date matches the earlier of the two times. .Pp +It is not possible to adjust a date to an invalid absolute day, so using +the switches +.Fl v No 31d Fl v No 12m +will simply fail five months of the year. +It is therefore usual to set the month before setting the day; using +.Fl v No 12m Fl v No 31d +always works. +.Pp Adjusting the date by months is inherently ambiguous because a month is a unit of variable length depending on the current date. This kind of date adjustment is applied in the most intuitive way. @@ -339,9 +347,9 @@ will display the last day of February in the year 2000: .Pp .Dl "Tue Feb 29 03:18:00 GMT 2000" .Pp -So will do the command: +So will the command: .Pp -.Dl "date -v30d -v3m -v0y -v-1m" +.Dl "date -v3m -v30d -v0y -v-1m" .Pp because there is no such date as the 30th of February. .Pp