bash extended glob - match files without prefix

Question

I'm trying to match filenames for a fail2ban jail - so I need to use filename globbing only - not regexes or bash scripting.

My /var/log/apache2 directory contains files including:

example.com.error.log
db.example.com.error.log
app1.example.com.error.log
app2.example.com.error.log

I'm trying to create a glob to match all files ending in .error.log except db.example.error.log - is this possible?

I've tried !(db)*.error.log but this still matches db.example.com.error.log. I'm guessing the !() is matching no characters, allowing the * to match from the beginning of the filename.

Note: I don't want to have to extend the glob when new appX logfiles are added, so I can't use @() with the list of currently-known non-db filenames.

(Background: I want to create a filter banning anyone requesting any phpMyAdmin URLs on any domain except db.example.com)

Answer 1

The extended filename globbing pattern (supported by bash with the extglob shell option activated, and also by ksh93)

!(db*).error.log

will ignore anything that starts with db.

To be more specific:

!(db.example.com).error.log

This will ignore any name in the current directory that starts with exactly db.example.com.

The !(db.example.com) pattern acts like a "special *" that will not match the the string db.example.com.

---

Your pattern,

!(db)*.error.log

excludes any name that starts with db, but allows any string after that, which obviously includes db.

By the same analogy as above, !(db) acts "like *" but won't match the exact string db, leaving us with the pattern **.error.log so to speak (with the first * being "special").