Question: It's hard to explain in the title.

I have a bash script that runs daily to backup one folder into a zip file. The zip files are named **world**`YYYYMMDD`**.zip** with `YYYYMMDD` being the date of backup. What I want to do is delete all but the 5 most recent backups. Sorting the files alphabetically will list the oldest ones first, so I basically need to delete all but the last 5 files when sorted in alphabetical order.

Answer: 
I can't test it right now because I don't have a Linux machine, but I think it should be:

```
rm `ls -A | head -5`

```
```
ls | grep ".*[\.]zip" | sort | tail -n-5 | while read file; do rm $file; done

```

* `sort` sorts the files
* `tail -n-5` returns all but the 5 most recent
* the `while` loop does the deleting