Can't delete file I own on Linux

Question

This is on a Debian box:

[ampeg]$ ls -la
total 36
dr-xr-xr-x 3 matt pg104272  4096 2011-01-27 10:37 .
drwxr-xr-x 3 matt pg104272  4096 2012-01-04 12:05 ..
-rwxrwxrwx 1 matt pg104272 11290 2012-01-02 06:41 default.settings.php
drwxrwxrwx 2 matt pg104272  4096 2012-01-04 11:56 files
-rwxrwxrwx 1 matt pg104272 10389 2011-01-27 10:34 settings.php
[ampeg]$ rm settings.php
rm: cannot remove `settings.php': Permission denied

I'm logged on as that matt user.

How is it possible that I can't delete that file?

Answer 1

You have no write access on that directory.

dr-xr-xr-x 3 matt pg104272  4096 2011-01-27 10:37 .

You can't delete a file within a directory you don't have write access to. Moreover, quoting the Ubuntu Community manual, "write access for a directory allows deleting of files in the directory even if the user does not have write permissions for the file".

Obtain write privileges, then you're good to go.