Why is /tmp diretory on my system showing 690 Mb full, whereas du -sh /tmp shows only 72K full?
drwxrwxrwt 2 lightdm lightdm 4096 Aug 29 21:49 at-spi2 drwx------ 2 ankit ankit 4096 Aug 29 21:50 keyring-0JTfoY drwx------ 2 ankit ankit 4096 Aug 29 21:44 keyring-rChLLL drwx------ 2 root root 16384 Jul 22 02:10 lost+found drwx------ 2 ankit ankit 4096 Jan 1 1970 orbit-ankit drwx------ 2 lightdm lightdm 4096 Aug 29 21:50 pulse-2L9K88eMlGn7 drwx------ 2 root root 4096 Aug 29 21:44 pulse-PKdhtXMmr18n drwx------ 2 ankit ankit 4096 Aug 29 21:50 pulse-zR1TZUAZfmQW drwx------ 2 ankit ankit 4096 Aug 29 21:44 ssh-dlslOXOq2203 drwx------ 2 ankit ankit 4096 Aug 29 21:50 ssh-MrQQVRyy3316 -rw------- 1 ankit ankit 0 Aug 29 21:45 tmp0qnNG4 -rw------- 1 ankit ankit 0 Aug 29 21:50 tmpVvSMt6 -rw------- 1 ankit ankit 0 Aug 29 21:49 tmpy9Gadz -rw-rw-r-- 1 lightdm lightdm 0 Aug 29 21:44 unity_support_test.0 ankit@duster:/tmp$ df -h df: `/home/ankit/.gvfs': Transport endpoint is not connected Filesystem Size Used Avail Use% Mounted on /dev/sda1 79G 11G 65G 14% / udev 2.9G 4.0K 2.9G 1% /dev tmpfs 1.2G 868K 1.2G 1% /run none 5.0M 0 5.0M 0% /run/lock none 2.9G 220K 2.9G 1% /run/shm /dev/sda7 38G 690M 35G 2% /tmp /dev/sda5 93G 26G 63G 30% /home /dev/sda6 93G 1.6G 87G 2% /boot /dev/sda3 154G 69G 78G 48% /home/mount_150 ankit@duster:/tmp$ ankit@duster:/tmp$ ankit@duster:/tmp$ sudo du -sh /tmp/ 72K 
1 Answer
It is possible for programs to unlink files but still keep them open. Such a file will still consume space until all programs stop accessing it, either by closing it or by terminating.
This is normal behaviour on Unix. It is common for programs to immediately unlink temporary files in this way in order to make sure that they disappear eventually.
Use lsof -a +L1 to see a listing of files in this state, together with the processes responsible.
