According to man lsof
, those are all regular files (REG
) that have been
). That is, the space used by those files has been labeled as being available for other uses, but not yet used. Remember, most Linux file systems (such as the default ext4
file system used by Ubuntu) avoid the problem of file fragmentation by trying very hard to only write a file to a disk area where the whole file can fit. When a file is "deleted," its INODE list is added to the available pool, but not actually used
'till it's needed. When you see a DEL
in the lsof
listing for a REG
file, it's just telling you that that file's space is available for use, and not counted in the used space in the file system.
In the list you posted, those files were used by the X-server for display windows that have been closed. The space will be reused when the server opens a new window.
Note that those files are all 8K bytes in size, so their total is not of any significance on your size of disk.
If you're concerned about what's eating your drive, look at the find
command. For example:
$ sudo find / -size +50M
[sudo] password for Peter:
find: `/proc/21908': No such file or directory
find: `/proc/21912/task/21912/fd/6': No such file or directory
find: `/proc/21912/task/21912/fdinfo/6': No such file or directory
find: `/proc/21912/fd/6': No such file or directory
find: `/proc/21912/fdinfo/6': No such file or directory
[many more lines...]
finds all files in my file system that are no smaller than 50 megabytes. (As you can see at the start of the output, since "everything is a file" in UNIX-like system, system memory (/proc/kcore
) is listed. If you don't want that, find
has a -type
option that would restrict it to regular files. See man find
or info find
) for more details.