Re: date minus one

From: Jared Still <jkstill_at_gmail.com>
Date: Wed, 30 Mar 2005 00:30:25 +0000
Message-ID: <bf463805032916304cda7e2a@mail.gmail.com>

And yet one more.

#!/bin/sh

# ydate: A Bourne shell script that
# prints yestarday's date
# Output Form: Month Day Year
# From Focus on Unix: http://unix.about.com

# Set the current month day and year.
month=`date +%m`
day=`date +%d`
year=`date +%Y`

# Add 0 to month. This is a
# trick to make month an unpadded integer. month=`expr $month + 0`

# Subtract one from the current day.
day=`expr $day - 1`

# If the day is 0 then determine the last # day of the previous month.
if [ $day -eq 0 ]; then

  # Find the preivous month.
  month=`expr $month - 1`

  # If the month is 0 then it is Dec 31 of   # the previous year.
  if [ $month -eq 0 ]; then
    month=12
    day=31
    year=`expr $year - 1`

  # If the month is not zero we need to find   # the last day of the month.
  else
    case $month in

      1|3|5|7|8|10|12) day=31;;
      4|6|9|11) day=30;;
      2)
        if [ `expr $year % 4` -eq 0 ]; then
          if [ `expr $year % 400` -eq 0 ]; then
            day=29
          elif [ `expr $year % 100` -eq 0 ]; then
            day=28
          else
            day=29
          fi
        else
          day=28
        fi
      ;;

    esac
  fi
fi

# Print the month day and year.
echo "$year/$month/$day"
exit 0

On Tue, 29 Mar 2005 12:55:06 -0600, Knight, Jon <jknight_at_concordefs.com> wrote:
> Just curious how the rest of the world gets "yesterday" in UNIX. We're
> running Solaris and we execute a sqlplus script with "select sysdate-1 from
> dual;" and pipe it to tail to set an environment variable.
>
> Is there a more UNIXy way, -or- maybe a java function. Any suggestions
> welcome.
>
> TIA,
> Jon Knight
>
> --
> http://www.freelists.org/webpage/oracle-l
>

-- 
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
--
http://www.freelists.org/webpage/oracle-l

Received on Tue Mar 29 2005 - 19:34:06 CST