Shell Programming and Scripting

I am writing an shell script , which reads a file with contents

Example :: (( This Format is yyyy-MM-DD))

2008-05-16
2008-05-17
2008-05-18
2008-05-19
2008-05-20
2008-05-21

when i run the shell script it has to check the current date and compare it with the todays date and give me the value which is one day less than that of todays date ..

when i execute DATE command it gives me this


Fri Mar 21 02:04:21 GMT 2008

so output should be 2008-05-20 , is there are no values then echo " no values present "


This is just to find what are all old in my unix box .. This is used in my routine work

Thanks

What do you think is the difference between Current date & Today's date?
And what are you trying to do with your input file?

Can you pls explain your problem clearly? Try and paste a bit code you've tried to develop so far..it will fetch you better & quicker replies.
Good luck!

Sorry .. i was not clear , these values are present in a file .. and i have to compare it with current date in unix box and give a result which is one day
more , and if there are no entries in the input file then result " NO values are present"

2008-05-16
2008-05-17
2008-05-18
2008-05-19
2008-05-20
2008-05-21
2008-05-22

Hi .. i am not sure of the code .. Please help me on this as i am new to this shell scripting

Thanks

You can use the following date format & use this value in any LOOP or Check condition

echo `date '+DATE:%d/%m/%Y%nTIME:%H:%M:%S'`

Pass the above date in a variable and use it..

Thanks for your replies .. but it didnot work !!

This is my input

I have a file a.txt which has the values which is YYYY-MM-DD format

[expires: 2008-03-29]
[expires: 2008-04-26]
[expires: 2008-05-26]
[expires: 2008-06-26]
[expires: 2008-07-26]

i need to chk the current date (systemdate) and compare it with a.txt if the expiring dates are with the range of 30 days it should print the line , else ignore the line and echo " no Keys are in expiring state"

I know that we can proceed on if conditons , but not sure of the date conversion .. Thanks for all your help !!

see this forum entry:

https://www.unix.com/tips-tutorials/3...tion-bash.html

for information and some excellent routines for manipulating dates and times.

Also a read through the man page for date will help you.

a possible solution off the top of my head without testing is:

Code:

while read line; do 
$expires=`echo $line | sed 's/^.*: \(.*\)$/\1'`
$timestamp=`date --utc --date "$expires" +%s`
$nowplus30days=`date --date "now +30 days"`
[ $nowplus30days -lt $timestamp ] && echo $line || echo "Key not in expiring state"
done < a.txt