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Linux / UNIX: List Open Files for Process

Q. How do I list all open files for a Linux or UNIX process using command line options?

A. Both Linux and UNIX like operating systems comes with various utilities to find out open files associated with process.

Task: UNIX List Open Files For Process

First use ps command to get PID of process, enter:
$ ps -aef | grep {process-name}
$ ps -aef | grep httpd

Next pass this PID to pfiles command,
$ pfiles {PID}
$ pfile 3533

Task: Linux List Open Files For Process

First you need to find out PID of process. Simply use any one of the following command to obtain process id:
# ps aux | grep {program-name}
$ ps -C {program-name} -o pid=
For example, find out PID of firefox web-browser, enter:
$ ps -C firefox -o pid=


To list opne files for firefox process, enter:
$ ls -l /proc/7857/fd
Sample output:

total 0
lr-x------ 1 vivek vivek 64 2008-03-05 22:31 0 -> /dev/null
l-wx------ 1 vivek vivek 64 2008-03-05 22:31 1 -> pipe:[18371]
lr-x------ 1 vivek vivek 64 2008-03-05 22:31 10 -> /usr/lib/firefox/firefox
l-wx------ 1 vivek vivek 64 2008-03-05 22:31 2 -> pipe:[18371]

lsof command

lsof command list open files under all Linux distributions or UNIX like operating system. Type the following command to list open file for process ID 351:
$ lsof -p 351

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{ 21 comments… add one }
  • Robert de Bock March 5, 2008, 5:22 pm

    Here is a cool lsof trick that shows you what port is in use by which program:

    lsof -iTCP:80

  • Eduardo García March 5, 2008, 6:50 pm

    lsof -p `ps -C firefox -o pid=`
    in a single line

  • Marco April 20, 2008, 2:57 pm

    For the single line lovers, here is another:

    lsof -p `pgrep firefox-bin`

    pgrep could be not automatically installed by your distro.

  • abhi July 14, 2009, 5:07 am

    Hi,,,, lsof is not giving the results in my Linux server,
    whenever i give the command ” lsof -u OSuser|wc -l ” its gives error saying “command not found”

  • kolmisoft September 13, 2009, 11:00 am

    netstat -vatupn

  • eldar52 November 23, 2009, 7:49 am

    How can i see all files that opened by a specific pid and all it’s threads.
    My C++ program opens 200 threads per process but i do not see all file descriptors that were opened by each thread.

  • javier December 4, 2009, 11:16 am

    Hi there,

    Is it possible to do it in the opposite direction. How to know which process created a particular file?

    I’ve just discovered your site, thanks a lot for sharing so much good stuff.


    • Sambodhi September 21, 2015, 1:25 pm

      It is possible to see which process has a particular file open using fuser.

  • kandrewo December 18, 2009, 3:25 pm

    I’m afraid there are no way to get process which created file. :(

  • Javier December 21, 2009, 5:31 pm

    What a pity! Thks for your help man.

  • shiprat April 7, 2010, 4:42 am

    >>> Is it possible to do it in the opposite direction. How to know which process created a particular file?

    if the file is open try

  • Elijah Saounkine June 9, 2010, 12:12 pm

    fuser -m (or . in case file is not accessible)
    will return all processes that have locked this file (or directory in case file is not accessible)
    then proceed as suggested with lsof -p | grep

  • Nafasat April 15, 2011, 3:02 pm

    What is man difference between lsof & pmap?

  • omfg April 2, 2012, 8:29 am

    Oneliner for Linux ; )
    lsof -p $(ps -ef | grep [PROGRAM_NAME] | grep -v grep | awk ‘{print $2}’)

  • ica May 4, 2012, 4:48 pm

    How could you get the files opened by a process using kernel modules?
    I mean, what would be the corespondent for ps aux | grep ?


  • Kiswono July 11, 2012, 2:53 am

    simpler way..

    lsof -c firefox
  • Jane August 23, 2012, 6:45 pm

    it doesn’t works when i try to do ‘lsof -p ‘ and got message as below
    /opt/csw/bin/lsof -p 22982
    lsof: can’t stat(/devices): No such file or directory

  • spb December 6, 2012, 7:35 pm

    I am using weblogic osb in red hat linux system,and the command pfiles is not found.
    My aim is to find File Descriptor’s total capacity

    command which i am running is:
    procfiles | grep rlimit

    Please help.

  • paulvc April 23, 2013, 1:06 am

    My server doesn’t have lsof installed.

    This works for me though:

    ls -l /proc/*/fd | grep

  • winky April 29, 2013, 5:29 am

    Yeah… lsof comes from something that used to be called ‘ofiles’ I think…. Hit nothing searching for ‘ofiles’ so I’m including this comment ! ;)

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