Shell Programming and Scripting

Hi guys,

I'm a newbie to shell script. I have to write a shell script that is supposed to give me a date which should be older than the current date when I supply "no. of days" as a command line parameter to the script.

(i.e)., if I am giving the no. of days value as 305, the script should give me the answer as date which is 305 days before today's date. The date can be in any format dd-mm-yyyy or mm/dd/yyyy, that is not a problem.

simply: (today's date - no of days) >>> should give the older date.

Looking forward to your "flooding" responses.

Thanks

In this post you will find all sort of date manipulation:
https://www.unix.com/showthread.php?t=13785

Hi thanks for the prompt response, I'll go through it. Meanwhile if someone has any inline scripts, pls don't hesitate to post it across. Thanks a lot once again.

hi royalibrahim,
take a look at gnu-date. it has some very powerfull date conversion built-in.
You can say stuff like:
date -d "10 day ago"
what make scripts very readable (as long you understand english).
I use the -d option very often to convert different date formats from programm to something our database likes.

Very useful info. Thanks a lot !!!

Hi, I have come across this weird behaviour of GNU date.

Code:

date -d "21-May-08 09:29 1 minute" +"%d-%b-%y %H:%M"

gives output: 21-May-08 09:30 --> Note: I have given here the abbreviated month name format specifier '%b'

But,

Code:

date -d "21-05-08 09:29 1 minute" +"%d-%m-%y %H:%M"

gives output: 08-05-21 09:30 --> I mean the year and the date field is jumbled, though I have given the correct format specifier '%m' for the month field. How to make it work?