How to find open file offset

abhibare · 01-20-2010, 11:12 AM

Hi all,

I have a program that takes a long time processing a large file. I am running it on SLES 10 (kernel 2.6.16.60). The process will most probably read the file from start to end. Is there a way to find out where the process currently is - like file offset?

lsof has "-o" option. But I read in some forums that it does not work on Linux. Does anybody know of any other way?

Thank you,
Abhijit

jf.argentino · 01-20-2010, 11:51 AM

--Nothing to deal the linux kernel--
By the way, assuming you're working in C, "ftell" is the function you're looking for

abhibare · 01-20-2010, 01:09 PM

Oops I didn't write the question clearly.

This is not my program. I want to know if it is possible to find file offset externally while a process is running. Does kernel allow that somehow?

Thanks for your reply.

jf.argentino · 01-20-2010, 03:03 PM

AFAIK, you can tell what program hold which file descriptor with lsof and fuser, but not sure if you can get more from that since the file descriptor offset is quite versatile...