]OT] Parsing postgresql.conf archive_command

Hello,

I'd like to get the path configured for archive_command in a shell script

I've used a file with following content as an example (postgresql.conf),

# archive_command = cp %p /backup/%r
# archive_command = cp %p /backup/%r
# archive_command = cp %p /backup/%r
#archive_command = cp %p /backup/%r
archive_command = 'cp %p /backup/wal/%f'

This is what I been trying.
$ awk '!/[ \t]*#/ { sub(/%f$/, "", $NF); print $NF }' postgresql.conf

and I get
/backup/wal/%f'

Any idea how to get rid of "%f'" so that I get only?
/backup/wal/

My regexp skills are sad :-)

Steve