UNIX for Dummies Questions & Answers

Hi I have yesterday date and todays date stored in two variables.

Today date is stored in variable -- testdate=`date +%m/%d/%Y`
I found the yesterday date and stored in variable -- ydate=$month'/'$day1'/'$year

Now i am trying to find out whether $testdate is less that $ydate.

I am finding this way in a IF condition

if [[ $toed -le $shud ]]
then
echo "yes correct time"
else
echo "not correct time"
fi
else

when i am executing this the condition is failing and going to else part.

PLease help me on this.

Thanks in advance.
Raju

One option is to convert the date to a number (the UNIX epoch)...

Code:

#!/usr/bin/perl
use Time::Local;
print timelocal(0,0,0,@ARGV[1],@ARGV[0]-1,@ARGV[2])."\n";

Call this with three numbers: month day year

For example, if you put the above in a script called Epoch, then:

Code:

testdate=$(Epoch $(date '+%m %d %Y'))
ydate=$(Epoch $month $day1 $year
 
if [ $testdate -le $ydate ]; then
...
fi

Another way is to convert 'MM/DD/YYYY' into 'YYYYMMDD' and compare numerically.

Code:

#!/bin/ksh93

date1="01/10/2009"
date2="06/10/2009"

if (( $(printf "%(%s)T" "$date1") > $(printf "%(%s)T" "$date2") ))
then
    echo "date1 is after date2"
else
    echo "date1 is not after date2"
fi

Thanks for you answer fpmurphy.

You code is working but i got little problem.
The printf command is not working for the T. So i have modified your command littel bit. See the command i have modified.

if (( $(printf "%s" "$toed") < $(printf "%s" "$shud") ))

toed and shud are the two variables which contains only date in the format 07/12/2009 and its working for date.
now i am storing two time values in the format 22:02:53. now i need to compare the times also. how do i full fill it.

Thanks in advance
Raju

Your "little bit" modification is invalid. You end up trying to numerically compare two strings. My example only works with Korn Shell 93 and requires the use of the %(%s)T syntax.

Hi It worked for me. now i am able to peform functions.

Thanks a lot.