I have question on shell scripting

learne · 07-15-2013, 10:05 PM

Hi Experts,

I have question on shell scripting, how can i get the first day of a month based on the date supplied.

for example, based on current date how can i get the first day of the month in.

thanks

Firerat · 07-15-2013, 10:22 PM

one way to do it

Code:

ncal | awk '$2 == "1" {print $1}'

Code:

Month=05
Year=2000
ncal -m $Month $Year | awk '$2 == "1" {print $1}'

but that isn't really shell scripting

shivaa · 07-15-2013, 10:32 PM

Just go through manual of follow comamnds:
http://linux.die.net/man/1/date
http://linux.die.net/man/1/cal

Just for hint, to display the current month:

Code:

~$ date +%m

To display the current month's calander:

Code:

~$ cal `date +%m` `date +%Y`

Then using these comamnds/combinations, you can extract the first day of month. So give it a try.

evo2 · 07-15-2013, 10:44 PM

Hi,

the first day of the month is the "1st".

Perhaps you want the day of the week for the first day of the current month:

Code:

date +%A --date=$(date +%Y-%m-01)

Or for a specific year and month Eg March 2012.

Code:

date +%A --date=2012-03-01

If this isn't what you want, can you please restate the question?

Cheers,

Evo2.

learne · 07-15-2013, 11:11 PM

Hi Experts,

i want the first days date of the month.

for example

if date is 15072013, i want 01070213 in dd/mm/yyyy format

so based on the date supplied as input i want to fetch its first day date.

regards,

Firerat · 07-15-2013, 11:29 PM

Quote:

Originally Posted by learne

Hi Experts,

i want the first days date of the month.

for example

if date is 15072013, i want 01070213 in dd/mm/yyyy format

so based on the date supplied as input i want to fetch its first day date.

regards,

Well, that is a little unexpected

Code:

Date=15072013
echo $Date | echo 01$(cut -c 3-)

Would do what you want, but is it what you need?

evo2's is better,

Code:

Date=15072013
date +%d/%m/%Y --date=$(echo $Date | cut -c 5-)-$(echo $Date | cut -c 3-4)-01

Code:

man date

Will help with the formatting of the output

But at the end of the day it depends where you get, and in what form your input is and what you want to do with it

Quote:

Originally Posted by learne

if date is 15072013, i want 01070213 in dd/mm/yyyy format

do you want 01/07/2013 or 01072013 ?

Sydney · 07-15-2013, 11:36 PM

dirty I know
echo 15072013 | awk -F "" {'print "01/"$3$4"/"$5$6$7$8'}

learne · 07-15-2013, 11:41 PM

#!/usr/bin/ksh

datestamp=`date '+%Y%m%d'`
yest=$((datestamp -1))
echo $yest

when i execute the above code i got the below output:
Output: 20130715

How can i display the same output in 15/07/2013, i tried with the format '+%d/%m/%y'` but i am getting error.

also how can i get the first day of the month based on the date which is fetched $yest=20130715.

for example: 01/07/2013 which is first day on the monthe

Any help.

Thanks

Firerat · 07-16-2013, 12:07 AM

Quote:

Originally Posted by learne

#!/usr/bin/ksh

datestamp=`date '+%Y%m%d'`
yest=$((datestamp -1))
echo $yest

when i execute the above code i got the below output:
Output: 20130715

How can i display the same output in 15/07/2013, i tried with the format '+%d/%m/%y'` but i am getting error.

also how can i get the first day of the month based on the date which is fetched $yest=20130715.

for example: 01/07/2013 which is first day on the monthe

Any help.

Thanks

OK, this is Dirty..

Code:

#!/usr/bin/ksh
function Yest {
Year=$1
Month=$2
Day=$3
YDay=$(expr $Day - 1)

date '+%A %d/%m/%Y' --date=${Year}-${Month}-${Day}
date '+%A %d/%m/%Y' --date=${Year}-${Month}-${YDay}
date '+%A %d/%m/%Y' --date=${Year}-${Month}-01
}

Yest $(date '+%Y %m %d')

passing 3 arguments to a function
The arguments are the output of date formatted such that we have spaces between year month and day
this is so we can easily manipulate the day ( to get yesterday )

Hope that makes sense

shivaa · 07-16-2013, 12:20 AM

If you're just concerned about printng the first date of given months in ddmmyyyy format according to provided date as input, then it can be done simply as:

Code:

#!/bin/bash
echo "Insert date: "; read mydate   ## Here you have to provide date format e.g. 15072013 as your input
month=$(echo $mydate| cut -c 3-4)
year=$(echo $mydate | cut -c 5-8)
echo 01$month$year

Firerat · 07-16-2013, 12:22 AM

ooops , what if date was 01/07/2013
yesterday would be 00 ???

so if YDay=0, must reduce Month by 1, and set YDay to last day of month.

Edit
getting yesterday is easy

[date]
date +%d/%m/%Y --date="yesterday"[/code]

learne · 07-16-2013, 12:33 AM

Hi Experts,

The question is i am trying to fetch the previous day using current date. for example if current date is 16/07/2013, i want previous day's date. i.e., 15/07/2013.

using current date fetch yesterday's date.

Input current date and output is current date - 1 - 15/07/2013.

how can i get this?

any suggestions

Firerat · 07-16-2013, 12:35 AM

Quote:

Originally Posted by learne

Hi Experts,

The question is i am trying to fetch the previous day using current date. for example if current date is 16/07/2013, i want previous day's date. i.e., 15/07/2013.

using current date fetch yesterday's date.

Input current date and output is current date - 1 - 15/07/2013.

how can i get this?

any suggestions

Turns out it is easy

Code:

date +%d/%m/%Y --date="yesterday"

learne · 07-16-2013, 12:42 AM

Quote:

Originally Posted by Firerat

Turns out it is easy

Code:

date +%d/%m/%Y --date="yesterday"

Hi,

When i executed the above code, i got the output as:

date +%d/%m/%Y --date="yesterday"
16/07/2013

i want previous date, i am new to scripting.

Firerat · 07-16-2013, 12:48 AM

Quote:

Originally Posted by learne

Hi,

When i executed the above code, i got the output as:

date +%d/%m/%Y --date="yesterday"
16/07/2013

i want previous date, i am new to scripting.

What time is it where you are ?

do

Code:

date
date --date="yesterday"