Check out the quickstart: [Lsof Quickstart][1]

I'm surprised no one mentioned the lsof quickstart file (included with lsof). Section "3.a" shows how to find open, unlinked files:

lsof -a +L1 *mountpoint*

E.g.:

 [root@enterprise ~]# lsof -a +L1 /tmp
 COMMAND PID USER FD TYPE DEVICE SIZE NLINK NODE NAME
 httpd 2357 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 mysqld 2588 mysql 4u REG 253,17 0 0 1495 /tmp/ibY0cXCd (deleted)
 mysqld 2588 mysql 5u REG 253,17 0 0 1496 /tmp/ibOrELhG (deleted)
 mysqld 2588 mysql 6u REG 253,17 0 0 1497 /tmp/ibmDFAW8 (deleted)
 mysqld 2588 mysql 7u REG 253,17 0 0 11387 /tmp/ib2CSACB (deleted)
 mysqld 2588 mysql 11u REG 253,17 0 0 11388 /tmp/ibQpoZ94 (deleted)
 httpd 3457 root 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 8437 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 8438 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 8439 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 8440 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 8441 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 8442 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 8443 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 8444 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 16990 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 19595 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 27495 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 28142 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)
 httpd 31478 apache 29u REG 253,17 3926560 0 1499 /tmp/.NSPR-AFM-3457-9820130.0 (deleted)

On Red Hat systems to find the local copy of the quickstart file, I usually do this:

 [root@enterprise ~]# locate -i quickstart |grep lsof
 /usr/share/doc/lsof-4.78/00QUICKSTART

...or this:

 [root@enterprise ~]# rpm -qd lsof
 /usr/share/doc/lsof-4.78/00.README.FIRST
 /usr/share/doc/lsof-4.78/00CREDITS
 /usr/share/doc/lsof-4.78/00DCACHE
 /usr/share/doc/lsof-4.78/00DIALECTS
 /usr/share/doc/lsof-4.78/00DIST
 /usr/share/doc/lsof-4.78/00FAQ
 /usr/share/doc/lsof-4.78/00LSOF-L
 /usr/share/doc/lsof-4.78/00MANIFEST
 /usr/share/doc/lsof-4.78/00PORTING
 /usr/share/doc/lsof-4.78/00QUICKSTART
 /usr/share/doc/lsof-4.78/00README
 /usr/share/doc/lsof-4.78/00TEST
 /usr/share/doc/lsof-4.78/00XCONFIG
 /usr/share/man/man8/lsof.8.gz


 [1]: http://www.akadia.com/services/lsof_quickstart.txt