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Date Validation not working

 
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# 1  
Old 06-02-2014
Date Validation not working
Hi Experts,

I have a date validation script in that i will validate the date for a given format and search in the logs for that date. The script logic is very simple like below.


Code:
Validate_Date()
{
is_valid=1
while [ $is_valid -ne 0 ]
do
 date_format=$(date "+$1")
 echo -e "Please enter the $2 date like - \033[0;32m$date_format\033[0;37m"
 read MY_DATE
 tmp=$(date "+$1" -d "$MY_DATE" 2>&1)
 if [ "${tmp:6:7}" == "invalid" ]; then
  is_valid=1
  echo -e "Invalid date $tmp"
 else
  MY_DATE=$tmp
  is_valid=0
 fi
done
}


This is working fine for almost all date format expect the below one

Code:
%d/%m/%Y

Whenever I pass some inputs which is valid its throwing error

Code:
$Validate_Date "%d/%m/%Y"
Please enter the  date like - 02/06/2014
25/05/2014
Invalid date date: invalid date `25/05/2014'
Please enter the  date like - 02/06/2014

The reason is server is always taking MMDDYYYY indeed of DDMMYYYY.

Code:
$date -d "30/06/2014" "+%d/%m/%Y"
date: invalid date `30/06/2014'
$date -d "25/05/2014" "+%d/%m/%Y"
date: invalid date `25/05/2014'


How to resolve this.

Thanks
Senthil
# 2  
Old 06-02-2014
Quote:
Originally Posted by senthil.ak
The reason is server is always taking MMDDYYYY indeed of DDMMYYYY.

Code:
$date -d "30/06/2014" "+%d/%m/%Y"
date: invalid date `30/06/2014'
$date -d "25/05/2014" "+%d/%m/%Y"
date: invalid date `25/05/2014'


How to resolve this.

Thanks
Senthil
From the manual:
Quote:
-d, --date=STRING
display time described by STRING, not ‘now’

DATE STRING
The --date=STRING is a mostly free format human readable date string
such as "Sun, 29 Feb 2004 16:21:42 -0800" or "2004-02-29 16:21:42" or
even "next Thursday". A date string may contain items indicating cal-
endar date, time of day, time zone, day of week, relative time, rela-
tive date, and numbers. An empty string indicates the beginning of the
day. The date string format is more complex than is easily documented
here but is fully described in the info documentation.

It recognizes:

Code:
date --date="1 days ago"
date --date="yesterday"
date --date='10 month ago'
date --date='2 hour ago'
date --date='Second Friday'

It will read this string always 30/06/2014 as MM/DD/YYYY regardless since it can not know what you mean otherwise.

And it is independent of the wanted output format "+%d/%m/%Y"
To fix it, you do not give it nn/nn/nnnn unless you mean MM/DD/YYYY

As a note, it doesn't know "new year" neither. Darn it! Smilie
Code:
date -d "new year"
date: invalid date `new year'

This User Gave Thanks to Aia For This Post:
senthil.ak
# 3  
Old 06-02-2014
So Aia, How to overcome the situation, I need to validate the date for the given format and if the format is not correct then i need to change or ask for the again. Do you have any logic please elaborate, thanks
# 4  
Old 06-02-2014
Quote:
Originally Posted by senthil.ak
So Aia, How to overcome the situation, I need to validate the date for the given format and if the format is not correct then i need to change or ask for the again. Do you have any logic please elaborate, thanks
As I mentioned before:
Quote:
To fix it, you do not give it nn/nn/nnnn unless you mean MM/DD/YYYY
Can you validate what I mean when I say 06/05/2014? Am I saying Jun 05 2014 or am I saying May 06 2014?

I suppose you might try at guessing, but it will not be validating it.
Unless you only accept one interpretation, you can not remove the ambiguity.
Last edited by Aia; 06-02-2014 at 11:20 PM..
# 5  
Old 06-03-2014
Hi Aia, Here i know the format, that is constant its either
Code:
 %d/%m/%Y or %Y/%m/%d

or any other format, we need to validate user input for the format. User inputs may vary and until we wont exit the loop unless user enters the correct format.
# 6  
Old 06-03-2014
Quote:
Originally Posted by senthil.ak
Hi Aia, Here i know the format, that is constant its either
Code:
 %d/%m/%Y or %Y/%m/%d

or any other format, we need to validate user input for the format. User inputs may vary and until we wont exit the loop unless user enters the correct format.
I suppose if you want to play guessing you can always try to convert anything that it is not %Y/%m/%d to it.

Some possibility in the shell
Code:
big_endian () {

data=${1}
segment1=${data%%/*}
segment3=${data##*/}
tmp=${data%/*}
segment2=${tmp#*/}

[[ "${segment1}" == ?? ]] && data="${segment3}/${segment2}/${segment1}"

echo ${data}
}

Maybe shell and external tr call
Code:
big_endian () {

data=${1}

segments=($(echo ${data} | tr '/' ' '))
[[ "${segments[0]}" == ?? ]] &&  data="${segments[2]}/${segments[1]}/${segments[0]}"

echo ${data} 
}

How about plain awk?
Code:
$date_string=$(echo $date_string | awk '{if ($1 ~ /^[0-9][0-9]$/){ print $3,$2,$1} else {print}}' FS='/' OFS='/')

As I said it is just playing a guessing game.
Last edited by Aia; 06-03-2014 at 05:04 AM..
# 7  
Old 06-03-2014
I Did some changes on the method and finally arrived to the below solution which works fine for me.
Code:
Validate_Date()
{
is_valid=1
while [ $is_valid -ne 0 ]
do
 date_format=$(date "+$1")
  echo -e "Please enter the $2 date like - \033[0;32m$date_format\033[0;37m"
 read MY_DATE
 #date "+$1" -d "$MY_DATE" 2>1 > /dev/null
 tmp=$(date "+$1" -d "$MY_DATE" 2>&1)
 if [ "${tmp:6:7}" == "invalid" ]; then
  is_valid=1
 else
  #MY_DATE=$tmp
  D=$(echo $1 | awk '{print substr($0,2,1)}')
  if [ "$D" == "d" -o "$D" == "D" ] ; then
   S=$(echo $tmp | awk '{print substr($0,3,1)}')
   MY_DATE=$(echo $tmp | awk -v "SEP=$S" 'BEGIN {FS = SEP;} {print $2SEP$1SEP$3}')
  else
   MY_DATE=$tmp
  fi
  is_valid=0
  MY_MONTH=$(date "+%b" -d "$tmp")
  MY_DAY=$(date "+%d" -d "$tmp")
 fi
done
}

 
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