Recently I observed that the /tmp on my Oracle Apps web tier (linux server) was 100% fill but when checking the /tmp location no files were visbible.

To find out the culprit execute

 lsof | grep /tmp |grep deleted

appsdev  23232  owner   50u   REG       1,22 1945679248         29 /tmp/filehdsj2.TMP (deleted)

The above file shows as deleted but still process is holding it. We need to identify the process and kill or restart the process\service.

ps -ef|grep  23232

Kill -9 23232

Once the process is free the /tmp space will be released.