+1

Reply:

Carl: Yup, there is. In the interest of full-disclosure, this is from an article from Sys Admin, "Date Arithmetic with the Shell" by Kyle Douglass and Ed Schaefer. They got the algorithm's from USNO: # This function computes the gregorian date from the julian date - $1. Returns a # date string of the form: MONTH DAY YEAR # See URL: http://aa.usno.navy.mil/faq/docs/JD_Formula.html for more information get_greg_from_JD () { typeset -i L typeset -i N typeset -i I typeset -i J typeset -i DAY typeset -i MON typeset -i YR L=$(($1+68569)) # $1 is the julian date N=$((4*L/146097)) L=$((L-(146097*N+3)/4)) I=$((4000*(L+1)/1461001)) L=$((L-1461*I/4+31)) J=$((80*L/2447)) DAY=$((L-2447*J/80)) L=$((J/11)) MON=$((J+2-12*L)) YR=$((100*(N-49)+I+L)) echo $MON $DAY $YR } TY=$(date '+%Y') # Year for today - MUST be YYYY TM=$(date '+%m') # Month for today TD=$(date '+%d') # Day for today # printf "%s %s %s\n" $TM $TD $TY JD=$(get_JD TD TM TY) # today's JD # yesterday's date yesterdays_date_str=$(get_greg_from_JD $((JD-1)) ) # parse yesterdays date string set - $(echo $yesterdays_date_str) echo $1 # month echo $2 # day echo $3 # year Regards, Nails

+1

Reply:

oh oh oh its very hard to work with dates under unix, because there is no spezify tool for it! my solution is, that "we" have a oracle server installed on the unix machine, so i can calculate the date with sql: backup_datum=`sqlplus -s EOF user/password set head off set feed off select to_char(sysdate - $1 ,'YYYYMMDD') from dual; EOF` this is another way to do it! regards Jonny

+1

Reply:

> this is another way to do it! Well clearly two possible solutions are described above. Perhaps you could explain a bit more why neither of them seems to be what you need.

+1

Reply:

@ William that is my old script: #!/bin/ksh #########################################################" # Script name : calculate_date.sh" # Path : /home/oracle/dba/bin" # Author : Jonny Schulz" # Rheinland Versicherungen" # Create : 27.06.2003" # Change :" # Of :" # Description" # This Script calculate Date." #########################################################" ##################### ### VARIABLES ### ##################### date=`date +'%Y.%m.%d'` yyyy=`date +'%Y'` yy=`date +'%y'` month=`date +'%m'` day=`date +'%d'` sign=$1 count=$2 format=$3 ##################### ### FUNCTIONS ### ##################### do_help() { echo "" echo "#########################################################" echo "# Script name : calculate_date.sh" echo "# Path : /home/oracle/dba/bin" echo "# Author : Jonny Schulz" echo "# Rheinland Versicherungen" echo "# Create : 27.06.2003" echo "# Change :" echo "# Of :" ec---" echo "# Description" echo "# This Script calculate Date." echo "#########################################################" echo "" echo " Please enter the following parameters:" echo " calculate_date.sh [+/-] [0123456789] [1/2/3/4/5/6/7/8]" echo "" echo " [+/-] = Art to calculate" echo " [0123456789] = Count days" echo " [1/2/3/4/5/6/7/8] = Which format" echo "" echo " Possible formats:" echo " ------------------" echo " YYYY.MM.DD (1)" echo " YYYYMMDD (2)" echo " YY.MM.DD (3)" echo " YYMMDD (4)" echo " DD.MM.YYYY (5)" echo " DDMMYYYY (6)" echo " DD.MM.YY (7)" echo " DDMMYYYY (8)" echo "" echo "" } minus() { while [[ $count != 0 ]] do count=$(($count-1)) case $month in 01 ) day=$(($day-1)) if [[ $day = 0 ]] then day=31 month=12 year=$(($year-1)) fi ;; 02 ) day=$(($day-1)) if [[ $day = 0 ]] then day=31 month=01 fi ;; 03 ) leap_year=`bc EOF scale=8 $year/4 EOF` leap_year=`echo $leap_year | cut -d'.' -f2` day=$(($day-1)) if [[ $day = 0 ]] then if [[ $leap_year = "00000000" ]] then day=29 month=02 else day=28 month=02 fi fi ;; 04 ) day=$(($day-1)) if [[ $day = 0 ]] then day=31 month=03 fi ;; 05 ) day=$(($day-1)) if [[ $day = 0 ]] then day=30 month=04 fi ;; 06 ) day=$(($day-1)) if [[ $day = 0 ]] then day=31 month=05 fi ;; 07 ) day=$(($day-1)) if [[ $day = 0 ]] then day=30 month=06 fi ;; 08 ) day=$(($day-1)) if [[ $day = 0 ]] then day=31 month=07 fi ;; 09 ) day=$(($day-1)) if [[ $day = 0 ]] then day=31 month=08 fi ;; 10 ) day=$(($day-1)) if [[ $day = 0 ]] then day=30 month=09 fi ;; 11 ) day=$(($day-1)) if [[ $day = 0 ]] then day=31 month=10 fi ;; 12 ) day=$(($day-1)) if [[ $day = 0 ]] then day=30 month=11 fi ;; esac done } plus() { while [[ $count != 0 ]] do count=$(($count-1)) case $month in 01 ) day=$(($day+1)) if [[ $day = 32 ]] then day=01 month=02 fi ;; 02 ) leap_year=`bc EOF scale=8 $year/4 EOF` leap_year=`echo $leap_year | cut -d'.' -f2` day=$(($day+1)) if [[ $leap_year = "00000000" ]] then if [[ $day = 30 ]] then day=01 month=03 fi else if [[ $day = 29 ]] then day=01 month=03 fi fi ;; 03 ) day=$(($day+1)) if [[ $day = 32 ]] then day=01 month=04 fi ;; 04 ) day=$(($day+1)) if [[ $day = 31 ]] then day=01 month=05 fi ;; 05 ) day=$(($day+1)) if [[ $day = 32 ]] then day=01 month=06 fi ;; 06 ) day=$(($day+1)) if [[ $day = 31 ]] then day=01 month=07 fi ;; 07 ) day=$(($day+1)) if [[ $day = 32 ]] then day=01 month=08 fi ;; 08 ) day=$(($day+1)) if [[ $day = 32 ]] then day=01 month=09 fi ;; 09 ) day=$(($day+1)) if [[ $day = 31 ]] then day=01 month=10 fi ;; 10 ) day=$(($day+1)) if [[ $day = 32 ]] then day=01 month=11 fi ;; 11 ) day=$(($day+1)) if [[ $day = 31 ]] then day=01 month=12 fi ;; 12 ) day=$(($day+1)) if [[ $day = 32 ]] then day=01 month=01 year=$(($year+1)) fi ;; esac done } ################ ### MAIN ### ################ case $format in 1 | 2 | 5 | 6 ) year=$yyyy ;; 3 | 4 | 7 | 8 ) year=$yy ;; * ) do_help ;; esac if [[ $sign = "+" ]] then plus else if [[ $sign = "-" ]] then minus else do_help fi fi case $day in 1 ) day="01" ;; 2 ) day="02" ;; 3 ) day="03" ;; 4 ) day="04" ;; 5 ) day="05" ;; 6 ) day="06" ;; 7 ) day="07" ;; 8 ) day="08" ;; 9 ) day="09" ;; esac case $year in 1 ) year="01" ;; 2 ) year="02" ;; 3 ) year="03" ;; 4 ) year="04" ;; 5 ) year="05" ;; 6 ) year="06" ;; 7 ) year="07" ;; 8 ) year="08" ;; 9 ) year="09" ;; esac case $format in 1 | 3 ) date_calculate=${year}.${month}.${day} ;; 2 | 4 ) date_calculate=echo ${year}${month}${day} ;; 5 | 7 ) date_calculate=echo ${day}.${month}.${year} ;; 6 | 8 ) date_calculate=echo ${day}${month}${year} ;; esac echo $date_calculate exit 0 unfortunately the runtime is bad! for this reason i create a new script and use the sql statement. i only had surch for a better script, but no script use a better runtime...