What do GDIR, GREG, VDIR, VREG mean in lsof output

filesystemslsof

The lsof manpage says the following about the TYPE column.

TYPE is the type of the node associated with the file – e.g., GDIR, GREG, VDIR, VREG, etc.

Can someone please explain (or point me to a link which explains) what these mean. I have tried googling on these but all the links take me to the lsof man page only.

If you find a link, do tell me how you googled it 🙂

Best Answer

Types starting with V are virtual types. That is, there is no corresponding inode on any physical disk but only a vnode in a virtual filesystem (like /proc). It seems those types only belong to BSD-like systems (AIX, Darwin, FreeBSD, HPUX, Sun etc.) and won't occur on a Linux system. As with the non-virtual types, DIR stands for directory and REG for a regular file.

I couldn't find the meaning of GDIR and GREG as they even don't appear in the lsof source code. But I guess they just stand for the non-virtual (generic?) directories and files.

Related Solutions

Linux – What do first column in /proc/mounts really mean in Linux

The first column is indeed the device as the documentation you quoted says. According to kernel.org documentation, rootfs is just a special case of a ramfs (in-RAM filesystem) that the kernel uses to make sure something is always mounted on /. It takes 0 or negligibly small space in RAM only and if you look further in /proc/mounts you should see the entry for the device containing your real root partition mounted on /.

How to interpret this output of lsof command

COMMAND     PID     USER   FD   TYPE DEVICE SIZE/OFF     NODE NAME
webalizer 32342 ctxmortg    5uW  REG   8,17    12288 32890954 /home2/ctxmortg/tmp/webalizer/eyebestdatedotcomauph.ctxmortgagemortgagerefi.com/dns_cache.db

FD - File Descriptor

If you are looking for file being written, look for following flag

# - The number in front of flag(s) is the file descriptor number of used by the process to associated with the file
u - File open with Read and Write permission
r - File open with Read permission
w - File open with Write permission
W - File open with Write permission and with Write Lock on entire file
mem - Memory mapped file, usually for share library

So 3r means webalizer has a descriptor number 3 associated with ...dns_cache.db, with read permission.

TYPE - File Type

In Linux, almost everything are files, but with different type.

REG - REGgular file, file that show up in directory
DIR - Directory

NODE

inode number in filesystem

You can find complete details in the man page.