Re: Bash script question

[Ben Breslauer <bbreslau@cs.oberlin.edu>]

Nate Bargmann wrote:
> I have a directory of files that are created daily using 
> filename-`date +%Y%m%d`.tar.gz so I have a directory with files whose
> names advance from filename-20061201.tar.gz to filename-20061202.tar.gz
> to filename-20061203.tar.gz and so on.  Based on the date in the
> filename, I would like to delete any than are X days older than today's
> date.  So, I'm not interested in the actual created/modified date, just
> the numeric string in the name.
>
> Despite working in Bash for the past ten years or so, my shell
> scripting skills are poor.  Logically, this seems like a simple test of
> whether the name is older than the current day - X, but I'm having
> trouble putting this into a script.

Here's a function, with an example invocation, that I'm pretty sure does 
what you want, assuming the file filename-20061203.tar.gz exists:

#!/bin/bash

# give $1=filename $2=days_old
function remove_if_too_old
{
  TODAY=`date +%Y%m%d`
  if [[ `echo "$1" | cut -f 2 -d "-" | cut -f 1 -d "."` < `expr $TODAY 
- $2` ]]
  then
    rm $1
  fi
}

remove_if_too_old filename-20061203.tar.gz 2

--Ben