UNIX for Dummies Questions & Answers

Hi, I have been trying just about every unix command to come up with yesterday's date (today's date - 1). I have seen all of the help on this forum, and none of it seems to work for me here. We are using Sun Solaris 9 Unix. I am using this script to create a .txt file with ftp commands that I will run from another script. All I want to do, is retrieve whatever files are at the ftp site with a date of yesterday in the filename. I have been trying to get the date right with Unix but obviously I am not having much luck.


I have tried a number of ways to get yesterday's date and none work for me.

#CalcDate=`date +%Y%m%d`
#CalcDate=`date -d yesterday +%Y%m%d`
#date="1 day ago" +"%Y%d%m"

I am able to output today's date to the .txt file using the following (see below).

CalcDate=`date +%Y%m%d`
cd /apps/PT8.44/outputs/backflow
echo 'lcd /apps/PT8.44/outputs/backflow/test' > bflowin.txt
echo 'mget *'$CalcDate* >> bflowin.txt
echo 'quit' >> bflowin.txt

Contents of bflowin.txt after script runs: I need it to be 20081119 (yesterday's date).

lcd /apps/PT8.44/outputs/backflow/test
mget *20081120*
quit

Any help you guys can give would be appreciated.

This is how I had to get yesterdays day (HP-UX):

Code:

OFFSET=${1:-1}

case $OFFSET in
  *[!0-9]* | ???* | 3? | 29) print -u2 "Invalid input" ; exit 1;;
esac

eval `date "+day=%d; month=%m; year=%Y`
typeset -Z2 day month
typeset -Z4 year

day=$((day - OFFSET))
if (( day <= 0 )) ;then
  month=$((month - 1))
  if (( month == 0 )) ;then
    year=$((year - 1))
    month=12
  fi
  set -A days `cal $month $year`
  xday=${days[$(( ${#days[*]}-1 ))]}
  day=$((xday + day))
fi

echo $day

or try:

Code:

date '+%m %d %Y' |  
{  
read MONTH DAY YEAR 
DAY=`expr "$DAY" - 1`  
case "$DAY" in  
        0)  
           MONTH=`expr "$MONTH" - 1`  
                case "$MONTH" in  
                        0)  
                           MONTH=12  
                           YEAR=`expr "$YEAR" - 1`  
                        ;;  
                esac  
        DAY=`cal $MONTH $YEAR | grep . | fmt -1 | tail -1`  
esac  
echo "Yesterday was: $MONTH $DAY $YEAR"  
}

Thanks Ikon......the second code example worked perfectly for me. I am no longer frustrated! Have a great weekend :-)