...determine yesterday's date in Unix environment? I...

Answer by ComputerGuy
Submitted on 1/19/2004
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# File-name: yesterday.sh #----------------------------------------------- # Returns date 1 day ago from the specified date # Current date is taken if no date is specified #----------------------------------------------- # Input: Default: # $1 - dd Current day # $2 - mm Current month # $3 - yyyy Current year #----------------------------------------------- #This is how a function is defined in a #UNIX shell scripts get_one_day_before_specified_date() { #get the command line input(date month & year) day=$1 month=$2 year=$3 # if it is the first day of the month if [ $day -eq 01 ] then # if it is the first month of the year if [ $month -eq 01 ] then # make the month as 12 month=12 # deduct the year by one year=`expr $year - 1` else # deduct the month by one month=`expr $month - 1` fi # use cal command, discard blank lines, # take last field of last line, # first awk command is used to get the # last useful line of the calendar cmd, # second awk command is used to get the # last field of this last useful line, # NF is no. of fields, # $NF is value of last field day=`cal $month $year \| awk 'NF != 0{ last = $0 }; END{ print last }' \| awk '{ print $NF }'` else # deduct the day by one day=`expr $day - 1` fi echo $day $month $year } #!/bin/ksh if [ $# -ne 3 ] then d=`date +%d` m=`date +%m` y=`date +%Y` else d=$1 m=$2 y=$3 fi #Cmd line arguments are captured in a shell script #through $1 $2 $3, ......., $9,${10} (not $10) # This is how we call unix user-defined functions, # notice it is not junk123( $1, $2, $3 ) format get_one_day_before_specified_date $d $m $y

Answer by Mohit Garg
Submitted on 10/11/2005
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Try this. It works well dd=`date +%d` mm=`date +%m` YY=`date +%Y` HH=`date +%H` MM=`date +%M` SS=`date +%S` let "today=(dd86400)+(HH3600)+(MM*60)+SS" let "yesterday=today-86400" let "y_YY=YY" let "y_mm=mm" let "y_dd=yesterday/86400" let "y_HH=(yesterday%86400)/3600" let "y_MM=((yesterday%86400)%3600)/60" let "y_SS=((yesterday%86400)%3600)%60" if (( dd==1 )) then let y_mm=mm-1 case $y_mm in 1\|3\|5\|7\|8\|10\|12 ) let y_dd=31 ;; 4\|6\|9\|11 ) let y_dd=30 ;; 2) if (( YY%4 == 0 )) then let y_dd=29 else let y_dd=28 fi ;; esac fi if (( mm==1 )) then let y_YY=YY-1 let y_mm=12 let y_dd=31 fi typeset -Z2 mm dd HH MM SS y_mm y_dd y_HH y_MM y_SS echo "Today : $YY/$mm/$dd $HH:$MM:$SS" echo "Yesterday : $y_YY/$y_mm/$y_dd $y_HH:$y_MM:$y_SS"

Answer by Gabbar
Submitted on 11/21/2006
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#! /usr/bin/ksh # Today's date TODAY=`date +'%m-%d-%Y'` # Setting month year & date MONTH=`echo $TODAY \| cut -d'-' -f1` DAY=`echo $TODAY \| cut -d'-' -f2` YEAR=`echo $TODAY \| cut -d'-' -f3` if test $DAY -eq 1 then if test $MONTH -eq 1 then YEAR=`expr $YEAR - 1` MONTH=12 DAY=31 echo $MONTH/$DAY/$YEAR exit fi if test $MONTH -eq 3 then MONTH=`expr $MONTH - 1` cal $MONTH $YEAR \| tail +2 \| grep -q 29 if test $? -eq 0 then DAY=29 else DAY=28 fi else MONTH=`expr $MONTH - 1` cal $MONTH $YEAR \| tail +2 \| grep -q 31 if test $? -eq 0 then DAY=31 else DAY=30 fi fi else DAY=`expr $DAY - 1` fi echo "$MONTH/$DAY/$YEAR"

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Question by Jim
Submitted on 1/2/2004
Related FAQ: comp.sys.hp.hpux FAQ
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How can i determine yesterday's date in Unix environment? I have Perl script that can do this but looking for one that can do this function in ksh.

Answer by shellmastergeneral
Submitted on 3/26/2004
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Linux (well, GNU date) only: date -d "1 day ago"

Answer by shellmastergeneral
Submitted on 3/26/2004
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BSD: YESTERDAY=`expr \`date +%s\` - 86400` date -r $YESTERDAY

Answer by ctsgnb
Submitted on 4/14/2004
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Almost all Unix : TZ=GMT+24 date (a Great Thanks to Patrice Allais for this handy tip !!!! )

Answer by d. pithon
Submitted on 5/17/2004
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GNU date is your (fantastic) friend $ date Mon May 17 15:12:45 CEST 2004 $ date -d yesterday Sun May 16 15:13:03 CEST 2004 $ date -d "Oct 10 1984 2 day ago" Mon Oct 8 00:00:00 CET 1984 $ date -d tomorrow Tue May 18 15:13:32 CEST 2004 $ date -d "2006-10-26 18:35:00 2 day ago" Tue Oct 24 18:35:00 CEST 2006 $ date -d "2006-10-26 18:35:00 2 day ago 3 hours" Tue Oct 24 21:35:00 CEST 2006 $ date -d "2006-10-26 18:35:00 2 day ago 3 hours ago" Sat Oct 28 15:35:00 CEST 2006

Answer by 8isgr8
Submitted on 3/17/2005
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You can also apply to formating date +%y%m%d -d"1 day ago" This returns 050316 I use this when I copy yesterdays log files and I want to keep the formating. YDAY=`date +%y%m%d -d"1 day ago"` I then zip it up for a windows friend ;) zip -r log"$YDAY" . -i \*.log

Answer by D.DASQUE
Submitted on 4/1/2005
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this command TZ=GMT+24 date must be adapt to your time zone i.e. (Your time zone )+24 example for France GMT+22

Answer by Splitz
Submitted on 5/12/2005
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FreeBSD.... 21 days ago = date -v-21d 1 month and 7 days ago = date -v-7d -v-1m

Answer by ulum
Submitted on 5/5/2006
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that's function is not valid. cause when we on, let's say 1 may 2006. on that date yesterday is 30 apr 2006 but its showing 0 may 2006

Answer by nyamijal
Submitted on 7/27/2006
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The following c prog should give the necessary output needed. #include <stdio.h> #include <time.h> int main() { time_t currenttime; time(¤ttime); currenttime = currenttime - 86400; printf("%s\n",ctime(¤ttime)); return 1; } compile it as 'cc yest_time.c -o yesterday' or with any of your faviourite compiler. then, # ./yesterday Wed Jul 26 11:35:45 2006 # date Thu Jul 27 11:37:00 IST 2006

Answer by wwiggens
Submitted on 10/3/2006
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Linux: yest (sourceforge.net/projects/yest)

Answer by MATA
Submitted on 11/23/2006
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GREAT HELP

Answer by dorg
Submitted on 3/2/2007
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To get month of yesterday GNU DATE YYYY-MM of yesterday date +"%Y-%m" -d yesterday

Answer by remo
Submitted on 3/22/2007
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DATE_STAMP=`TZ=CST+24 date +%y%m%d` http://www.unix.com/showthread.php?s=&threadid=13731

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