fuser

UNIX for Beginners Q & A UNIX for Dummies Questions & Answers
1

Anyone ever use fuser,
i tried this command fuser /database.bk
but it only returns datbase.bk:

I read some of the forums online, one of them said when he used fuser, it broke down the box, i really don't want that happen.

I thought fuser is to see who is accessing that file, right?
any help is greatly appreciated. i have been searching online, and there is not that much help on fuser.

thanks.

2

The command fuser is used to list processes using a file. If nothing is return, then the file is not use by anyone at that time. If the file is used, you will get the PID of users using the file:

 
unixbox:/ # fuser YOURFILE
YOURFILE:     8316o    5452o    2351o    5426o    1393o   26348o   24673o
8886o   28688o   16107o   18838o   11514o   29396o    3810o   15796o

I don't see how fuser command could cause any problem to your system, maybe someone has an other opinion.

3

If running fuser causes a problem to occur, the system was broken before fuser was run. But I have never seen anything like that happen.

4

thanks for your reply. yes, you are right, no one was using that file.
yes, it is strange that fuser will bring down the system. don't think so either.

thanks.

5

Strange question, but.. how do you actually OPEN a file to test this behaivour ? I ask this because I tried with vi thefile but fuser shows another process different than the session where I actually executed vi thefile. Which leads me to think that probably vi open up a new version of the file to edit it.

6

Try:
sleep 5000 < somefile

7

Thanks Perderabo. And I was wrong, problem is that I was using echo $$ before I ran vi somefile, and obviously, the process invoked by 'vi somefile' is different than the one I was seeing from the terminal. I just needed to use ps to see the process vi actually used when fuser'ing the file. Great!

8

try lsof, I like it much more...

9

Hello ,

here under an interessant use of fuser with -u optioon ( see more on man :p)
its display the PID + USER of the process accessing the file :

fuser -u messages
messages: 230o(root)
ps -edf|grep 230|grep -v grep
root 230 1 0 Jan 15 ? 0:02 /usr/sbin/syslogd