I just want to know, how do we calculate the months in shell scripting.
If i give the input as 20-01-2011, the output should be 20-02-2011, 20-03-2011 or 20-04-2011........
How do i get this ?
Cheers.
not sure exactly what you mean...do you want all months for a given year ? or all successive months, or just next month?
here's a start point for you to have a play with:
# for x in {1..12}; do printf "20-%02d-2011\n" $x ;done
20-01-2011
20-02-2011
20-03-2011
20-04-2011
20-05-2011
20-06-2011
20-07-2011
20-08-2011
20-09-2011
20-10-2011
20-11-2011
20-12-2011
HTH
ksh93 has date arithmetic.
Hi Tytalus,
Thanks for your time....
What I need is, for example I am providing the input as 01-01-2011.
The system should accept it and increment it by one month and should display the output as 01-02-2011.
Similarly if the input is 01-12-2011, the output should be 01-01-2012.
Any solution for this will be of great help.....
Cheers.
Your solution is not so simple as to add one to the month and to handle the year.
What if your input is: 01-31-2011
What is your expected output?
ms:/home/unxsa/functions>today
27May2011
ms:/home/unxsa/functions>today -p 30
26Jun2011
ms:/home/unxsa/functions>cat today
# Name: today
#
# Purpose: Prints today's date, plus or minus the given number of days.
# Default is today's date.
#
# Date: 2006/06/08
#
# Version: 1.0
#
# Required Parameters:
# -------------------------------------------------------------------------
#
# Optional Parameters:
# -f [format]- format of date to use
# -p #- number of days to add
# -m #- number of days to subtract
# -c c- character to use in the date string
# -s- use short year string
# -------------------------------------------------------------------------
#
# Change History:
#
# Date Name Comments
# _________________________________________________________________________
# 2006/06/08 selbyp Created.
# 21 jan 2011 purdym converted to ksh93
#
#
#
#
#
#
#
#
#
#
#
#
###################################################################################
# function
###################################################################################
function today {
USAGE=":f:p:m:c:sh"
FORMAT=0
PLUS=0
MINUS=0
SEPCHAR=""
SHORT=0
if [[ $# -gt 0 ]]
then
while getopts "${USAGE}" OPT
do
case ${OPT} in
f) FORMAT=${OPTARG};;
p) PLUS=${OPTARG};;
m) MINUS=${OPTARG};;
c) SEPCHAR=${OPTARG};;
s) SHORT=1;;
h) cat <<EOF
Syntax: today { [-p n] OR [-m n] } [-f FORMAT] [-c CHAR] [-s] [-h]
Parameters:
[-p n]-Print today's date, plus n days
[-m n]-Print today's date, minus n days
[-f FMT]-Print date using specified format (DMY/MDY/YMD), default looks like Jun092006
[-c c]-Separate dates using the character c
[-s]-Use a short year in the date
[-h]-View this help
Default: Print today's date in the default format.
EOF
return 0
;;
?) echo "today(): unrecognized option: ${OPT}"
return 1;;
esac
done
shift $((${OPTIND} - 1))
ARGUMENTS=$@
if (( ${PLUS} != 0 && ${MINUS} != 0 ))
then
RETCODE=1
(( ${DEBUG} != 0 )) && print "today(): Attempted to add and subtract simultaneously."
return $RETCODE
fi
if [[ ${FORMAT} -ne 0 && ${FORMAT} != "YMD" && ${FORMAT} != "MDY" && ${FORMAT} != "DMY" ]]
then
RETCODE=2
(( ${DEBUG} != 0 )) && print "today(): Unrecognized format: ${FORMAT}"
return $RETCODE
fi
if (( ${#SEPCHAR} > 1 ))
then
RETCODE=3
(( ${DEBUG} -ne 0 )) && print "today(): Bad separating character: ${SEPCHAR}"
return $RETCODE
fi
fi
eval `date "+DAY=%d; MONTH=%m; YEAR=%Y`
if (( $PLUS > 0 ))
then
DAY=$((DAY + PLUS))
elif (( $MINUS > 0 ))
then
DAY=$((DAY - MINUS))
fi
if (( $DAY <= 0 ))
then
while (( $DAY <= 0 ))
do
MONTH=$((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))
done
else
set -A DAYS $(cal $MONTH $YEAR)
MAXDAY=${DAYS[$((${#DAYS
[*]} - 1 ))]}
if (( $DAY > $MAXDAY ))
then
while (( $DAY > $MAXDAY ))
do
DAY=$((DAY - MAXDAY))
MONTH=$((MONTH + 1))
if (( MONTH > 12 ))
then
YEAR=$((YEAR + 1))
MONTH=1
fi
set -A DAYS $(cal $MONTH $YEAR)
MAXDAY=${DAYS[$((${#DAYS
[*]} - 1 ))]}
done
fi
fi
if (( $SHORT != 0 ))
then
if (( ${#YEAR} == 4 ))
then
OLD_YEAR=${YEAR}
typeset -Z2 YEAR
YEAR=$( echo ${OLD_YEAR} | cut -c 3-4 )
elif (( ${#YEAR} != 2 ))
then
if [[ ! -z $DEBUG ]] && [[ $DEBUG -gt 0 ]]
then
echo "today(): what kind of year is this: ${YEAR}??"
return 1
fi
fi
fi
typeset -Z2 F_DAY F_MONTH
F_DAY=$DAY
F_MONTH=$MONTH
if [[ $FORMAT == "YMD" ]]
then
print "${YEAR}${SEPCHAR}${F_MONTH}${SEPCHAR}${F_DAY}"
elif [[ $FORMAT == "DMY" ]]
then
print "${F_DAY}${SEPCHAR}${F_MONTH}${SEPCHAR}${YEAR}"
elif [[ $FORMAT == "MDY" ]]
then
print "${F_MONTH}${SEPCHAR}${F_DAY}${SEPCHAR}${YEAR}"
else
case $F_MONTH in
01) MONTH_STR=Jan;;
02) MONTH_STR=Feb;;
03) MONTH_STR=Mar;;
04) MONTH_STR=Apr;;
05) MONTH_STR=May;;
06) MONTH_STR=Jun;;
07) MONTH_STR=Jul;;
08) MONTH_STR=Aug;;
09) MONTH_STR=Sep;;
10) MONTH_STR=Oct;;
11) MONTH_STR=Nov;;
12) MONTH_STR=Dec;;
esac
print ${F_DAY}${MONTH_STR}${YEAR}
fi
}
read DATE; date -d "$DATE 1 month"