How do I get the end of next month date and deal with leap years. 1

[markmulligansr]

How do I get the end of next month's date and deal with end of year and February during leap years?

Is there a UNIX command that returns this or do I have to develop some sort of script logic using the date command.

The requirements I have are, given today's date, what is the end of next month's date in the format of MM/DD/CCYY where MM is next month, DD is the last day of next month and CCYY is the century and year of next month.

Thanks in advance.

 

[mrregan]

maybe clumsy, but here goes:

month=`date +%m -d "next month"`
year=`date+%Y -d "next month"`
for day in `cal $month $year`
do
lastday=$day
done
echo $month"/"$lastday"/"$year

 

[markmulligansr]

Thanks. I found this code and it works for the end of year and leap year scenarios.

function pn_month {
typeset ym=$1 pn=$2
(( m = ym % 100 ))
(( y = ym / 100 ))
while (( pn != 0 )); do
if (( pn > 0 )); then
if (( m == 12 ))
then (( m = 1 )); (( y = y + 1 ))
else (( m = m + 1 ))
fi
(( pn = pn - 1 ))
else
if (( m == 1 ))
then (( m = 12 )); (( y = y - 1 ))
else (( m = m - 1 ))
fi
(( pn = pn + 1 ))
fi
done
printf "%s\n" $(( 100*y + m ))
}

function end_month {
typeset ym=$1 y m ld
(( y = ym / 100 ))
(( m = ym % 100 ))
for ld in $(cal $m $y); do :; done
if [ $m -lt 10 ]
then m="0${m}"
fi
echo "${m}/${ld}/${y}"
}

function begin_month {
typeset ym=$1 y m ld
(( y = ym / 100 ))
(( m = ym % 100 ))
for ld in $(cal $m $y); do :; done
if [ $m -lt 10 ]
then m="0${m}"
fi
echo "${m}/01/${y}"
}

pn_month "`date +%Y%m`" +1 | read NextMonth
end_month $NextMonth | read EndOfNextMonth
begin_month $NextMonth | read BeginOfNextMonth

 

[stefanwagner]

unformated:

date -d $(date +%Y-%m -d+2month)-01-1day

Take (inner brace) the date of now + 2 months.
Use Year and month. (2010-10-)
Append -01: 2010-10-01
Substract (outer commdand) 1day.

Formatted to your needs:

date +%M/%d/%Y -d $(date +%Y-%m -d+2month)-01-1day

Source: man date
which says:
"The date string format is more complex than is easily documented here but is fully described in the info documentation."
The infopages (info date) tell you more.

don't visit my homepage:

http://home.arcor.de/hirnstrom/minis/index.html

 

[stefanwagner]

I'm sorry, maybe a random incidence yesterday, that %m and %M (month, minute) lead the same result.

date +%m/%d/%Y -d $(date +%Y-%m -d+2month)-01-1day

don't visit my homepage:

http://home.arcor.de/hirnstrom/minis/index.html

 

[Annihilannic]

Stefan's algorithm implemented in PERL, which you may find more ubiquitous than the GNU version of date:

[gray]#!/usr/bin/perl -w[/gray]
[url=http://perldoc.perl.org/functions/use.html][black][b]use[/b][/black][/url] [green]strict[/green][red];[/red]
[black][b]use[/b][/black] [green]POSIX[/green][red];[/red]
[url=http://perldoc.perl.org/functions/my.html][black][b]my[/b][/black][/url] [red]([/red][url=http://perldoc.perl.org/functions/undef.html][black][b]undef[/b][/black][/url],[black][b]undef[/b][/black],[black][b]undef[/b][/black],[black][b]undef[/b][/black],[blue]$mon[/blue],[blue]$year[/blue],[black][b]undef[/b][/black],[black][b]undef[/b][/black],[black][b]undef[/b][/black][red])[/red] = [url=http://perldoc.perl.org/functions/localtime.html][black][b]localtime[/b][/black][/url][red];[/red]
[url=http://perldoc.perl.org/functions/print.html][black][b]print[/b][/black][/url] strftime [red]"[/red][purple]%m/%d/%Y[purple][b]\n[/b][/purple][/purple][red]"[/red],[black][b]localtime[/b][/black][red]([/red][maroon]mktime[/maroon][red]([/red] [fuchsia]0[/fuchsia], [fuchsia]0[/fuchsia], [fuchsia]0[/fuchsia], [fuchsia]0[/fuchsia], [blue]$mon[/blue]+[fuchsia]2[/fuchsia], [blue]$year[/blue] [red])[/red][red])[/red][red];[/red]

Annihilannic.