Hello everybody...
I'm a Unix newbie and i just got this task at work to figure out what's wrong with a daily script my team is using.
The idea behind the script is that it takes the day before in a yyyymmdd format, find files with that date in a specific directory and executes an (irrelavant) operation on them.
The problem with the script is that it won't work in every 1st of every month. So in every 1st of each month they need to change the script manualy.
I think that it has to do with the $d-1 section so in eache 1st of the month it thinks that the day before is 0.
My task is to figure out a way to change the script so it will work every day of the month including the 1st of every month.
It's my first day on a new job and i dont know anything about scripting so please be gentle. I'd appreciate it if you could find a way to correct it and explain it to me.
The relevant lines are these:
d=`date '+%d'`
d=`/usr/bin/expr $d - 1`
if [ $d -lt 10 ]
then
DATE=`date '+%Y%m'`0$d
else
DATE=`date '+%Y%m'`$d
fi
DATE='20060831'
cd ${root_dir}
num=`ls -1 dec_${DATE}*|wc -l`>/dev/null
if [ $num -lt 21 ] #if [ $num -lt 1 ]
then
I had discovered a small bug in my code later. Here's the fully updated code. It takes care of previous month, previous year, leap year issues while calculating yesterday's date.
#! /bin/sh
###########################################################################################
## This scripts runs in 2 ways #
## First way: without command line arguments. It calculates yesterday's date #
## Second way: 3 numeric argumnets(dd mm yyyy). Calculates date prior to the input date #
###########################################################################################
case $# in
3)
[[ `echo $1 | grep [[:alpha:]]` || `echo $1 | grep [[:punct:]]` ]] && echo -e "$1 is not a number.\nQuitting" && exit 1
[[ `echo $2 | grep [[:alpha:]]` || `echo $2 | grep [[:punct:]]` ]] && echo -e "$2 is not a number.\nQuitting" && exit 1
[[ `echo $3 | grep [[:alpha:]]` || `echo $3 | grep [[:punct:]]` ]] && echo -e "$3 is not a number.\nQuitting" && exit 1
YEAR=$3
NMONTH=$2
DATE=$1
# Add a 0 in front if month or date is single digit; i.e. < 10
[[ ${#NMONTH} -eq 1 ]] && NMONTH="0$NMONTH"
[[ ${#DATE} -eq 1 ]] && DATE="0$DATE"
[[ $DATE > 31 || $DATE < 01 ]] && echo -e "Invalid date.\n Quitting" && exit 1
[[ $DATE > 30 && ($NMONTH == 04 || $NMONTH == 06 || $NMONTH == 09 || $NMONTH == 11) ]] && echo -e "Invalid date.\n Quitting" && exit 1
[[ $NMONTH > 12 || $NMONTH < 01 ]] && echo -e "Invalid month.\n Quitting" && exit 1
[[ ${#YEAR} -ne 4 ]] && echo -e "Invalid Year.\n Quitting" && exit 1
if [[ $NMONTH == 02 && $DATE > 28 ]]; then # Month is February, no. of days greater than 28
if [[ `expr $YEAR % 4` != 0 ]]; then # If not divisible by 4, can't be a leap year
echo -e "Invalid date. \n Quitting" && exit 1
else # If divisible by 100 but not divisible by 400, can't be a leap year
[[ `expr $YEAR % 100` == 0 && `expr $YEAR % 400` != 0 ]] && echo -e "Invalid date. \n Quitting" && exit 1
fi
[[ $DATE > 29 ]] && echo -e "Invalid date. \n Quitting" && exit 1
fi
;;
*)
YEAR=`date +"%Y"`
NMONTH=`date +"%m"`
DATE=`date +"%d"`;;
esac
if [[ $DATE == 01 || $DATE == 1 ]]; then # If its the first day of the month, set yesterday's date accordingly.
case $NMONTH in
01|02|04|06|08|09|11)
DATE=31
if [[ $NMONTH == "01" || $NMONTH == "1" ]]; then
YEAR=`expr $YEAR - 1`
NMONTH=12;LMONTH="December"
else
NMONTH=`expr $NMONTH - 1`
fi;;
03) if [[ `expr $YEAR % 4` == 0 ]]; then #Year divisible by 4
if [[ `expr $YEAR % 100` == 0 ]]; then #YEAR divisible by 100
DATE=29
if [[ `expr $YEAR % 400` != 0 ]]; then #YEAR not divisible by 400 is not a leap year
DATE=28
fi
else
DATE=29
fi
else
DATE=28
fi
NMONTH=`expr $NMONTH - 1`;;
*)
DATE=30
NMONTH=`expr $NMONTH - 1` ;;
esac
else
DATE=`expr $DATE - 1`
fi
# If numeric month or date is <10, add a 0 in front
if [ ${#NMONTH} -eq 1 ]; then
NMONTH="0$NMONTH"
fi
if [ ${#DATE} -eq 1 ]; then
DATE="0$DATE"
fi
case $NMONTH in # set long month name
01) LMONTH="January";;
02) LMONTH="February";;
03) LMONTH="March";;
04) LMONTH="April";;
05) LMONTH="May";;
06) LMONTH="June";;
07) LMONTH="July";;
08) LMONTH="August";;
09) LMONTH="September";;
10) LMONTH="October";;
11) LMONTH="November";;
12) LMONTH="December";;
esac
echo $DATE-$NMONTH-$YEAR-$LMONTH #Output date-month-year
Some changes will be required to make it accept yyyymmdd date as input. currently it expects dd mm yyyy as input.
