#From: damatex@CAM.ORG (Mario Boudreault) #Newsgroups: comp.unix.shell #Subject: JULIAN DATE CONVERSION SUB #Date: 4 Aug 1995 10:23:28 -0400 #Message-ID: <3vtah0$jb3@ocean.CAM.ORG> #For those using shells and who want to convert dates to a julian number #here is a shell script (wihtout validation) that can be used as a base #program for your shell scripts. #Special thanks to Ed Ferguson@ti.com who sent me the algorithm to compute #that date. # # MODIFIED BY CHET RAMEY TO CONVERT TO bash v2 SYNTAX # # cnvdate - Conversion de dates en julienne et vice et versa... # # Par : Mario Boudreault Damatex Inc Montreal, Canada # Date: 2 Aout 1995 # Rev.: 2 Aout 1995 # # Usage: # cvdate [-j] YYYMMDD pour convertir en nbre de jours # cvdate -d {julian number} pour convertir en AAAAMMJJ # jul_date() { # # Separe ANNEE, MOIS et JOUR... # YEAR=`echo $DATE | awk ' { print substr($0,1,4) } '` MONTH=`echo $DATE | awk ' { print substr($0,5,2) } '` DAY=`echo $DATE | awk ' { print substr($0,7,2) } '` # # Execute la formule magique... # A=$(( $DAY - 32075 + 1461 * ( $YEAR + 4800 - ( 14 - $MONTH ) / 12 ) \ / 4 + 367 * ( $MONTH - 2 + ( 14 - $MONTH ) / 12 * 12 ) / 12 - \ 3 * ( ( $YEAR + 4900 - ( 14 - $MONTH ) / 12 ) / 100 ) / 4 )) echo $A } day_date() { TEMP1=$(( $DATE + 68569 )) TEMP2=$(( 4 * $TEMP1 / 146097 )) TEMP1=$(( $TEMP1 - ( 146097 * $TEMP2 + 3 ) / 4 )) Y=$(( 4000 * ( $TEMP1 + 1 ) / 1461001 )) TEMP1=$(( $TEMP1 - 1461 * $Y / 4 + 31 )) M=$(( 80 * $TEMP1 / 2447 )) D=$(( $TEMP1 - 2447 * $M / 80 )) TEMP1=$(( $M / 11 )) M=$(( $M + 2 - 12 * $TEMP1 )) Y=$(( 100 * ( $TEMP2 - 49 ) + $Y + $TEMP1 )) M=`echo $M | awk ' { M=$0 ; if ( length($0) == 1 ) M="0"$0 } END { print M } '` D=`echo $D | awk ' { D=$0 ; if ( length($0) == 1 ) D="0"$0 } END { print D } '` echo $Y$M$D } # main() if [ $# -eq 1 ]; then DATE=$1 jul_date elif [ "$1" = '-j' ]; then DATE=$2 jul_date elif [ "$1" = '-d' ]; then DATE=$2 day_date fi # # Termine # exit 0