Why is there filename "socket" in lsof output when I use nedit command?

L1P0 · 03-02-2020, 08:59 PM

I just want to know why there is a file "socket" open when I use nedit command..

Quote:

COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME

nedit 3979 mxoper 1w FIFO 0,7 696805771 pipe
nedit 3979 mxoper 2w FIFO 0,7 696805771 pipe
nedit 3979 user1 3u unix 0xa830e180 731194794 socket

Also, Why do the node numbers reach 700,000,000+ ? It is beyond the max number set as shown by df -i.

Details on my system:

Quote:

Linux 2.6.9-67.ELhugemem #1 SMP Fri Nov 16 13:04:12 EST 2007 i686 i686 i386 GNU/Linux

Quote:

Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/sda3 59932672 510982 59421690 1% /
/dev/sda1 60240 52 60188 1% /boot
none 437711 1 437710 1% /dev/shm

ulimit -a output:

Quote:

time(cpu-seconds) unlimited
file(blocks) unlimited
coredump(blocks) 0
data(kbytes) unlimited
stack(kbytes) 10240
lockedmem(kbytes) 32
memory(kbytes) unlimited
nofiles(descriptors) 2048
processes 55277

berndbausch · 03-03-2020, 12:24 AM

Because it opened a UNIX socket. Since nedit is a GUI program, this is not surprising. The socket could be used to communicate with the graphics server.

Sockets are not files, but inter-process communication channels. The offset 731194794 is probably the number of bytes that have been written to the socket so far. It's a large number, but again, if this is communication with the graphics server, not too surprising.

L1P0 · 03-03-2020, 04:41 AM

Quote:

Originally Posted by berndbausch

Because it opened a UNIX socket. Since nedit is a GUI program, this is not surprising. The socket could be used to communicate with the graphics server.

Sockets are not files, but inter-process communication channels. The offset 731194794 is probably the number of bytes that have been written to the socket so far. It's a large number, but again, if this is communication with the graphics server, not too surprising.

Thanks! About the node numbers.. I have experimented it. Tried to open a file with a 116-byte size using nedit. I grep the socket opened and it was 1451898. Then I close the nedit. Tried to open again the same file using nedit. But, this time, the node number was 1452642. It incremented!

pan64 · 03-03-2020, 05:11 AM

https://unix.stackexchange.com/quest...les-in-proc-fd and https://unix.stackexchange.com/quest.../190606#190606

that is not an inode number, but something like "device" number, it just identifies the socket itself.

ehartman · 03-03-2020, 06:56 AM

Quote:

Originally Posted by L1P0

I just want to know why there is a file "socket" open when I use nedit command..

NEdit can be a server and probably has this socket available (too?) for the

Quote:

nc - Client program for NEdit text editor

(from its man page)
Another quote from that man page

Quote:

If no server is running, nc will start one unless configured otherwise.
Client/server mode is useful for integrating NEdit with software development environments, mailers, and other programs; or just as a quick way to open files from the shell command line without starting a new NEdit session.

So yes, a socket is used for inter-program communication.

Because of a name conflict (with nc=netcat) I have renamed this "nc" to "nclient"

berndbausch · 03-03-2020, 08:26 AM

Quote:

Originally Posted by L1P0

Thanks! About the node numbers.. I have experimented it. Tried to open a file with a 116-byte size using nedit. I grep the socket opened and it was 1451898. Then I close the nedit. Tried to open again the same file using nedit. But, this time, the node number was 1452642. It incremented!

The numbers are not node numbers. They (look like they) are under the column "SIZE". Perhaps this would be clearer if you formatted the output as code.