topic Re: date manipulating in Operating System - HP-UX

date manipulating

Matt Dunfee — Tue, 09 Oct 2001 19:19:12 GMT

Does anyone know a simple way to script the previous days' date? More specifically, "current day - 1".

Re: date manipulating

linuxfan — Tue, 09 Oct 2001 19:29:04 GMT

Hi Matt,

There a number of ways you can do it

1. YD=`TZ=aaa24 date +%Y%m%d`
this will store yesterdays date in YD in the format YYMMDD

2.Yesterday=`TZ=PST+24 date +%D`
this will give it in the format 10/08/01

3. export YD=$(perl -e 'print scalar localtime(time-1*86400),"\n"' |cut -c 5-11)

this will just store Oct 8 in YD variable.

-HTH
Ramesh

Re: date manipulating

harry d brown jr — Tue, 09 Oct 2001 19:29:47 GMT

It's not pretty:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,11866,0x06ed660142b2d5118ff10090279cd0f9,00.html

Re: date manipulating

Santosh Nair_1 — Tue, 09 Oct 2001 19:30:01 GMT

Try playing around with the TIMEZONE environment variable.

echo $(sh -c "TZ=$(date +%Z)+24; export TZ; date '+%m%d%y'")

See this URL for more info:

http://www.dutchworks.nl/htbin/hpsysadmin?h=3&dn=19828&q=date%20script&fh

-Santosh

Re: date manipulating

A. Clay Stephenson — Tue, 09 Oct 2001 19:36:34 GMT

Hi:

I'll give you my standard answer. I always use Julian days to do this - astromers use this method so that leap years, months, ... don't make calculations messy. If you call the attached script with no args, it converts today's date into a Julian Day (~ number of days since 4004 BCE); subtract 1 from this and feed that number in and it returns a calendar date. This method will work across any number of days past or future.

e.g.

#!/usr/bin/sh
TODAYJDATE=`caljd.sh`
PREVJDATE=$(( ${TODAYJDATE} - 1))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"

Clay

Re: date manipulating

Matt Dunfee — Tue, 09 Oct 2001 19:44:29 GMT

Ramesh - Using
Yesterday=`TZ=CST+24 date +%D` works perfect! The only stipulation is, how could I filter for weekends to display Friday's date on Monday?

Thanks!!

Re: date manipulating

A. Clay Stephenson — Tue, 09 Oct 2001 19:52:34 GMT

Now Matt, we are getting to the beauty of true Julian Dates: When supplied with -w caljd.sh returns the weekday (0 - Sun; 6 -Sat.)

So:

#!/usr/bin/sh
TODAYJDATE=`caljd.sh`
TODAYWKDAY=`caljd.sh -w`
NDAYS=1
#if Monday subtract 3 else subtract 1
if [ ${TODAYWKDAY} -eq 1 ]
then
NDAYS=3
fi
PREVJDATE=$(( ${TODAYJDATE} - ${NDAYS} ))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"

Clay

Re: date manipulating

James R. Ferguson — Tue, 09 Oct 2001 19:57:50 GMT

Hi Matt:

The trick posted by Ramesh only works +-24 hours, so that you can get tomorrorw's or yesterday's date but nothing beyond those bounds.

Regards!

...JRF...

Re: date manipulating

linuxfan — Tue, 09 Oct 2001 20:13:07 GMT

Hi Matt,

As pointed out by James and as you have already found out, my suggestion only works for +/- 24 hours, the best way to achieve what you want is to use the caljd.sh script provided by clay.

You could do something like this

/Begin/
#!/usr/bin/ksh

# THis script calculates the previous date of weekdays
# Uses caljd.sh

PATH=/usr/bin:/usr/local/bin:
# You do want to modify the path to include the caljd.sh script

TODAYJDATE=`caljd.sh`
TODAY_WK_DAY=`caljd.sh -w`

if [ $TODAY_WK_DAY -ge 2 -a $TODAY_WK_DAY -le 5 ]
then
{
PREVJDATE=$(( ${TODAYJDATE} - 1))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"
}
elif [ $TODAY_WK_DAY -eq 1 ]
then
{
PREVJDATE=$(( ${TODAYJDATE} - 3))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"
}
elif [ $TODAY_WK_DAY -eq 0 ]
then
{
PREVJDATE=$(( ${TODAYJDATE} - 2))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"
}
elif [ $TODAY_WK_DAY = 6 ]
then
{
PREVJDATE=$(( ${TODAYJDATE} - 1))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"
}
fi

/End/

This would work for all the scenarious

-HTH
Ramesh

Re: date manipulating

linuxfan — Tue, 09 Oct 2001 20:16:29 GMT

Hi again,

Modified version,

/Begin/

#!/usr/bin/ksh

# THis script calculates the date depending on weekdays
# Uses caljd.sh

PATH=/usr/bin:/usr/local/bin:~/admin/scripts

TODAYJDATE=`caljd.sh`
# TODAY_WK_DAY=`caljd.sh -w`
TODAY_WK_DAY=6

if [ $TODAY_WK_DAY -ge 2 -a $TODAY_WK_DAY -le 6 ]
then
{
PREVJDATE=$(( ${TODAYJDATE} - 1))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"
}
elif [ $TODAY_WK_DAY -eq 1 ]
then
{
PREVJDATE=$(( ${TODAYJDATE} - 3))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"
}
elif [ $TODAY_WK_DAY -eq 0 ]
then
{
PREVJDATE=$(( ${TODAYJDATE} - 2))
PREVDATE=`caljd.sh ${PREVJDATE}`
echo "Yesterday was ${PREVDATE}"
}
fi

/End/

-Regards
Ramesh