Searching for unknown date inside the file and replace to new date

Shell Programming and Scripting
1

Hello,

Iam a newbies to Shell scripting. Iam trying to replace the date inside the file to new date. is there anyway that we can just use the pattern to search as "[0-9]..." I have many files want to replace with the same date, and each file contains different date.

Thanks for your help.

~Daro

2

Please post a sample of the input file and the expected output.
And use code tags while posting code and data samples.

3

Thanks for a quick response.
ex: file.txt
Today is 2012-10-04.

and I would like to change the date inside the file "2012-10-04" to new date. I know how to replace it as "s/olddate/newdate/", this way I need to get into the file to get the old date that I would like to change. But this ways takes time since I have many files and each file contains different date.
Please help me to use "pattern" instead.

Thanks.

Daro