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Unix Script: Loop over all days of a month
Posted on 2016-10-25
Dear Experts,
What I want to do in a bash script, I provide the pseudo code
currentDate=script execution date
for all days in previous month (relative to currentDate)
currentLoopDate=Date in the format: YYYY-DD-MM
end for
e.g. if I run the script now, October 25
in the loop my first date string should be 2016-01-10
in the loop my second date string should be 2016-02-10
in the loop my last date string should be 2016-31-10
What I want to do in a bash script, I provide the pseudo code
currentDate=script execution date
for all days in previous month (relative to currentDate)
currentLoopDate=Date in the format: YYYY-DD-MM
end for
e.g. if I run the script now, October 25
in the loop my first date string should be 2016-01-10
in the loop my second date string should be 2016-02-10
in the loop my last date string should be 2016-31-10
[X]
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17 Comments
Active today
which date do we have today?
date '+%Y-%m-%d'
expr `date '+%Y%m' - 1` | sed -e 's/\(....\)/\1-'
day=`expr `date '+%Y%m' - 1` | sed -e 's/\(....\)/\1-'`-01
Active today
Here is an example, please format the output as per your requirement and update ref_days with all months
/home>cat ref_days.txt ### month|days
10|31
/home>cat loop_date.sh
#!/usr/bin/sh
var_currdate=`date "+%Y-%d-%m"`
var_currmonth=`echo ${var_currdate}|awk -F'-' '{print $3}'`
var_date=`echo ${var_currdate}|awk -F'-' '{print $2}'`
echo $var_currdate $var_currmonth ${var_date}
if [[ `grep $var_currmonth ref_days.txt|wc -l` -eq 1 ]]
then
var_loopdays=`cat ref_days.txt|awk -F'|' '{print $2}'`
var_loop1=`expr $((${var_date}-1))`
counter=1
while [[ $counter -le $var_loop1 ]]
do
var_monthstartdate_calc=`e
echo "day $counter `date -d "-${var_monthstartdate_cal
counter=`expr $(($counter+1))`
done
counter=${var_date}
while [[ ${counter} -le $var_loopdays ]]
do
var_monthstartdate_calc=`e
echo "day ${counter} `date -d "+${var_monthstartdate_cal
counter=`expr $(($counter+1))`
done
else
echo "invalid month"
fi
/home>. ./loop_date.sh
2016-25-10 10 25
day 1 Sat Oct 1 12:45:56 EDT 2016
day 2 Sun Oct 2 12:45:56 EDT 2016
day 3 Mon Oct 3 12:45:56 EDT 2016
day 4 Tue Oct 4 12:45:56 EDT 2016
day 5 Wed Oct 5 12:45:56 EDT 2016
day 6 Thu Oct 6 12:45:56 EDT 2016
day 7 Fri Oct 7 12:45:56 EDT 2016
day 8 Sat Oct 8 12:45:56 EDT 2016
day 9 Sun Oct 9 12:45:56 EDT 2016
day 10 Mon Oct 10 12:45:56 EDT 2016
day 11 Tue Oct 11 12:45:56 EDT 2016
day 12 Wed Oct 12 12:45:56 EDT 2016
day 13 Thu Oct 13 12:45:56 EDT 2016
day 14 Fri Oct 14 12:45:56 EDT 2016
day 15 Sat Oct 15 12:45:56 EDT 2016
day 16 Sun Oct 16 12:45:56 EDT 2016
day 17 Mon Oct 17 12:45:56 EDT 2016
day 18 Tue Oct 18 12:45:56 EDT 2016
day 19 Wed Oct 19 12:45:56 EDT 2016
day 20 Thu Oct 20 12:45:56 EDT 2016
day 21 Fri Oct 21 12:45:56 EDT 2016
day 22 Sat Oct 22 12:45:56 EDT 2016
day 23 Sun Oct 23 12:45:56 EDT 2016
day 24 Mon Oct 24 12:45:56 EDT 2016
day 25 Tue Oct 25 12:45:56 EDT 2016
day 26 Wed Oct 26 12:45:56 EDT 2016
day 27 Thu Oct 27 12:45:56 EDT 2016
day 28 Fri Oct 28 12:45:56 EDT 2016
day 29 Sat Oct 29 12:45:56 EDT 2016
day 30 Sun Oct 30 12:45:56 EDT 2016
day 31 Mon Oct 31 12:45:56 EDT 2016
/home>cat ref_days.txt ### month|days
10|31
/home>cat loop_date.sh
#!/usr/bin/sh
var_currdate=`date "+%Y-%d-%m"`
var_currmonth=`echo ${var_currdate}|awk -F'-' '{print $3}'`
var_date=`echo ${var_currdate}|awk -F'-' '{print $2}'`
echo $var_currdate $var_currmonth ${var_date}
if [[ `grep $var_currmonth ref_days.txt|wc -l` -eq 1 ]]
then
var_loopdays=`cat ref_days.txt|awk -F'|' '{print $2}'`
var_loop1=`expr $((${var_date}-1))`
counter=1
while [[ $counter -le $var_loop1 ]]
do
var_monthstartdate_calc=`e
echo "day $counter `date -d "-${var_monthstartdate_cal
counter=`expr $(($counter+1))`
done
counter=${var_date}
while [[ ${counter} -le $var_loopdays ]]
do
var_monthstartdate_calc=`e
echo "day ${counter} `date -d "+${var_monthstartdate_cal
counter=`expr $(($counter+1))`
done
else
echo "invalid month"
fi
/home>. ./loop_date.sh
2016-25-10 10 25
day 1 Sat Oct 1 12:45:56 EDT 2016
day 2 Sun Oct 2 12:45:56 EDT 2016
day 3 Mon Oct 3 12:45:56 EDT 2016
day 4 Tue Oct 4 12:45:56 EDT 2016
day 5 Wed Oct 5 12:45:56 EDT 2016
day 6 Thu Oct 6 12:45:56 EDT 2016
day 7 Fri Oct 7 12:45:56 EDT 2016
day 8 Sat Oct 8 12:45:56 EDT 2016
day 9 Sun Oct 9 12:45:56 EDT 2016
day 10 Mon Oct 10 12:45:56 EDT 2016
day 11 Tue Oct 11 12:45:56 EDT 2016
day 12 Wed Oct 12 12:45:56 EDT 2016
day 13 Thu Oct 13 12:45:56 EDT 2016
day 14 Fri Oct 14 12:45:56 EDT 2016
day 15 Sat Oct 15 12:45:56 EDT 2016
day 16 Sun Oct 16 12:45:56 EDT 2016
day 17 Mon Oct 17 12:45:56 EDT 2016
day 18 Tue Oct 18 12:45:56 EDT 2016
day 19 Wed Oct 19 12:45:56 EDT 2016
day 20 Thu Oct 20 12:45:56 EDT 2016
day 21 Fri Oct 21 12:45:56 EDT 2016
day 22 Sat Oct 22 12:45:56 EDT 2016
day 23 Sun Oct 23 12:45:56 EDT 2016
day 24 Mon Oct 24 12:45:56 EDT 2016
day 25 Tue Oct 25 12:45:56 EDT 2016
day 26 Wed Oct 26 12:45:56 EDT 2016
day 27 Thu Oct 27 12:45:56 EDT 2016
day 28 Fri Oct 28 12:45:56 EDT 2016
day 29 Sat Oct 29 12:45:56 EDT 2016
day 30 Sun Oct 30 12:45:56 EDT 2016
day 31 Mon Oct 31 12:45:56 EDT 2016
Hi Abhimanu,
thx I am running this script under AIX and getting errors: date: illegal option --d usage: date [-] [+Field Descriptors]
thx I am running this script under AIX and getting errors: date: illegal option --d usage: date [-] [+Field Descriptors]
Dear Hanno
I am running the script at AIX
the command
day=`expr `date '+%Y%m' - 1` | sed -e 's/\(....\)/\1-'`-01
gives an error
syntax error at line 1 : '|' unexpecgted
I am running the script at AIX
the command
day=`expr `date '+%Y%m' - 1` | sed -e 's/\(....\)/\1-'`-01
gives an error
syntax error at line 1 : '|' unexpecgted
Active today
Let's do it step by step:
1. Get today's date as "a number" consisting of current year and month
1. Get today's date as "a number" consisting of current year and month
date '+%Y%m'
day=`date '+%Y%m' `
echo $day
day=`expr $day - 1'
echo $day
Active today
The srcipt Abhimanu provided looks pretty good to me!
Have you checked if this works?
Have you checked if this works?
date "+%Y-%d-%m"
var_currdate=`date '+%Y-%d-%m'`
echo $var_currdate
@Hanno
Yes I've checked the script
got an error (have to man date)
errors: date: illegal option --d usage: date [-] [+Field Descriptors]
And I did not fully understand yet, how a correct number of days for a month is picked if the ref_days.txt contains all the monts|days
Yes I've checked the script
got an error (have to man date)
errors: date: illegal option --d usage: date [-] [+Field Descriptors]
And I did not fully understand yet, how a correct number of days for a month is picked if the ref_days.txt contains all the monts|days
Active today
Does this work?
If not, check you man page for date's format string options
date '+%Y-%d-%m'
If not, check you man page for date's format string options
Active today
Hi mruff,
Good to say up front what flavour of UNIX you're using, especially if it's something like AIX.
I think AIX probably doesn't ship with GNU date.
But to confirm, what output does this give you?:
And will you be running this as root, or as another user? (It could make a difference to my approach. I can explain later if required.)
Good to say up front what flavour of UNIX you're using, especially if it's something like AIX.
I think AIX probably doesn't ship with GNU date.
But to confirm, what output does this give you?:
date -d 'next month'
date -v -1m +%Y%m%d
And will you be running this as root, or as another user? (It could make a difference to my approach. I can explain later if required.)
Active today
Hi again nruff,
I decided on a different strategy.
Firstly, where you wrote this:
"for all days in previous month (relative to currentDate)"
I assume you mean this:
"for all days in current month (relative to currentDate)"
based on your example. Right?
currentDate = 2016-27-10
2016-01-10
2016-02-10
2016-03-10
2016-04-10
2016-05-10
2016-06-10
2016-07-10
2016-08-10
2016-09-10
2016-10-10
2016-11-10
2016-12-10
2016-13-10
2016-14-10
2016-15-10
2016-16-10
2016-17-10
2016-18-10
2016-19-10
2016-20-10
2016-21-10
2016-22-10
2016-23-10
2016-24-10
2016-25-10
2016-26-10
2016-27-10
2016-28-10
2016-29-10
2016-30-10
2016-31-10
Is that what you want?
I decided on a different strategy.
Firstly, where you wrote this:
"for all days in previous month (relative to currentDate)"
I assume you mean this:
"for all days in current month (relative to currentDate)"
based on your example. Right?
#!/bin/bash
currentDate=`date +'%Y-%d-%m'`
echo "currentDate = $currentDate" # Remove this if you don't need it
yyyy=`echo $currentDate | cut -c-4`
mm=`echo $currentDate | cut -c9-`
daysInMonth=`cal | tr '\n' ' ' | awk '{print $NF}'`
day=1
while [ $day -le $daysInMonth ]
do
currentLoopDate=`printf %d-%02d-%02d $yyyy $day $mm`
echo $currentLoopDate # Remove this if you don't need it
let day=$day+1
done
currentDate = 2016-27-10
2016-01-10
2016-02-10
2016-03-10
2016-04-10
2016-05-10
2016-06-10
2016-07-10
2016-08-10
2016-09-10
2016-10-10
2016-11-10
2016-12-10
2016-13-10
2016-14-10
2016-15-10
2016-16-10
2016-17-10
2016-18-10
2016-19-10
2016-20-10
2016-21-10
2016-22-10
2016-23-10
2016-24-10
2016-25-10
2016-26-10
2016-27-10
2016-28-10
2016-29-10
2016-30-10
2016-31-10
Is that what you want?
@tel2 sorry did not notice your answer until now
I've requested from moderator to select yours as best solution and provide 300 point to you
I've requested from moderator to select yours as best solution and provide 300 point to you
@all, I reassigned the points as Abhimuanyu posted first and most likely put most effort in his solution I've assigned him a little more point then to you tel2.
I hope the points assignment is considered fair by all of you
thank you all for your assistance, with all your help I've finished my script
I hope the points assignment is considered fair by all of you
thank you all for your assistance, with all your help I've finished my script
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