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18
votes
2answers
4k views

Who's got the other end of this unix socketpair?

I want to determine what process has the other end of a unix socket, that was created with socketpair(). I have a program parent which creates a socketpair(AF_UNIX, SOCK_STREAM, 0, fds), and fork()s. ...
18
votes
1answer
12k views

ulimit: difference between hard and soft limits

What is the difference between hard and soft limits in ulimit? For number of open files, I have a soft limit of 1024 and a hard limit of 10240. It is possible to run programs opening more than 1024 ...
17
votes
4answers
4k views

How do I find out which processes are preventing unmounting of a device?

Sometimes, I would like to umount a usb device, but I get a drive is busy error. How do I find out which processes or programs are accessing the device?
16
votes
3answers
8k views

Why is number of open files limited in Linux?

Right now, I know that: Find open files limit per process: ulimit -n Count all opened files by all process: lsof | wc -l Get maximum open files count allowd: cat /proc/sys/fs/file-max My ...
14
votes
3answers
2k views

Monitor what is being sent to /dev/null?

Just for fun: Is there a way to monitor/capture/dump whatever is being written to /dev/null? On Debian, or FreeBSD, if it matters, any other OS specific solutions are also welcome.
14
votes
2answers
3k views

How do open files behave on linux systems?

I just renamed a log file to "foo.log.old", and assumed that the application will start writing a new logfile at "foo.log". I was surprised to discover that it tracked the logfile to its new name, and ...
13
votes
3answers
1k views

Where do open file handles go when they die?

What happens to the files that are deleted while they have a file handle open to them? I have been wondering this ever since I figured out I could delete a video file while it was playing in MPlayer ...
12
votes
2answers
4k views

/proc/PID/fd/X link number

In Linux, in /proc/PID/fd/X, the links for file descriptors that are pipes or sockets have a number, like: l-wx------ 1 user user 64 Mar 24 00:05 1 -> pipe:[6839] l-wx------ 1 user user 64 Mar 24 ...
11
votes
5answers
3k views

What is using this network socket?

I'm trying to use NTP to update the time on my machine. However, it gives me an error: host # ntpdate ntp1.example.org 10 Aug 12:38:50 ntpdate[7696]: the NTP socket is in use, exiting What does the ...
11
votes
1answer
2k views

How do I monitor opened files of a process in realtime?

I know I can view the open files of a process using lsof at that moment in time on my Linux machine. However, a process can open, alter and close a file so quickly that I won't be able to see it when ...
9
votes
2answers
1k views

How to find out the file offset of an opened file?

My problem is that with lsof -p pid I can find out the list of opened file of a process whose process id is pid. But is there a way to find out the file offset of each accessed file ? Please give me ...
9
votes
2answers
2k views

What happens when I close() a file descriptor?

I am trying to get the whole picture with file descriptors. Say I have process1 which initially has these file descriptors: _process1_ | | | 0 stdin | | 1 stdout | | 2 stderr | ...
9
votes
1answer
128 views

Strategies for maintaining a reference to a file after it was moved or renamed?

I've had a mac at work lately, and was amazed to see that Xcode would still find my latest project after I renamed its folder and moved it someplace else. Now I understand that this is the result of ...
8
votes
4answers
2k views

How can same fd in different processes point to the same file?

Say I have process 1 and process 2. Both have a file descriptor corresponding to the integer 4. In each process however the file descriptor 4 points to a totally different file in the Open File Table ...
8
votes
6answers
2k views

How do I set a limit on the number of files Linux can have open?

I plan to run a Java app using nohup ... &. The limit must apply to commands like this.
7
votes
3answers
22k views

Alternatives for “lsof” command?

In many cases "lsof" is not installed on the machines that with I have to work, but the "function" of lsof would be needed very much (ex. on AIX). :\ Are there any "lsof" like applications in the ...
7
votes
2answers
3k views

See the STDOUT redirect of a running process

If I start an app with this command: /path/to/my/command >> /var/log/command.log And the command doesn't return, is there a way, from another prompt, to see what the STDOUT redirect is set ...
7
votes
1answer
494 views

file descriptors and /dev/fd

Are file descriptors unique across a process, or throughout the whole system. Because every file seems the use the same descriptor for stdin and stdout. Is there something special with these? How ...
7
votes
3answers
3k views

How to remove Notepad from the applications list?

After installing Wine, Notepad has became a default application to open unknown textual files by double click. I'd like to eliminate this behaviour and remove Notepad from the list of applications ...
6
votes
2answers
8k views

Find and remove large files that are open but have been deleted

How does one find large files that have been deleted but are still open in an application? How can one remove such a file, even though a process has it open? The situation is that we are running a ...
5
votes
2answers
178 views

How does bash continue to work correctly when you move its working directory?

On Linux, I moved a directory to another directory using mv, and in another shell, my working directory happened to be the directory that was moved. I ran hg pull in that shell, and to my surprise, ...
5
votes
3answers
778 views

vim: How to switch to the directory listing from file view?

I have opened a dir vim some/dir. I can navigate within the tree, yet once I opened a file I wonder, how do I close the file view in order to go back to the directory listing to navigate to another ...
5
votes
2answers
439 views

Recover deleted file that is currently being written to

I started downloading a big file and accidently deleted it a while ago. I know how to get its current contents by cping /proc/<pid>/fd/<fd> but since the download is still in progress ...
5
votes
2answers
2k views

How to find out which file is currently written by a process

My situation is that from time to time a specific process (in this case, it's Thunderbird) doesn't react to user input for a minute or so. I found out using iotop that during this time, it writes ...
5
votes
2answers
2k views

Change default applications used by gnome-open, exo-open, xdg-open, gvfs-open and kde-open

How to change the applications associated with certain file-types for gnome-open, exo-open, xdg-open, gvfs-open and kde-open? Is there a way by editing config files or by a command-line command? Is ...
5
votes
3answers
696 views

rewrite existing file so that it gets replaced by new version atomically, only once fully written

I vaguely recall reading somewhere that there used to be, in some Unices a way to open an existing file for writing, with a flag that asked the kernel to use the old version (for other processes ...
5
votes
1answer
1k views

File descriptor limits are lost after a system reboot

I'm trying to increase the default file descriptor limits for processes on my system. Specifically I'm trying to get the limits to apply to the Condor daemon and its sub-processes when the machine ...
5
votes
0answers
97 views

How can different file descriptors point to the same file in open file table? [duplicate]

Possible Duplicate: How can same fd in different processes point to the same file? I have a hard time grasping the two ideas of File Descriptor Table and Open File Table. Open File Table ...
4
votes
2answers
169 views

Emacs' file extension recognition

How do I get Emacs to recognize new file extensions? For example if I have a .c file and I open it in Emacs, I get the correct syntax highlighting for C, but if I have a .bob file format (which I know ...
4
votes
2answers
1k views

What is the referent of a file descriptor?

My understanding is that a file descriptor is an integer which is a key in the kernel's per-process mapping to objects such as open()ed files, pipes, sockets, etc. Is there a proper, short, and ...
4
votes
1answer
1k views

How do I tell a script to wait for a process to start accepting requests on a port?

I need a command that will wait for a process to start accepting requests on a specific port. Is there something in linux that does that? while (checkAlive -host localhost -port 13000 == false) ...
4
votes
2answers
45 views

Portability of file descriptor links

I've always wondered this but never took the time to find out, so I'll do so now - how portable is the usage shown here of either /proc/$$/fd/$N or /dev/fd/$N? I understand POSIX guarantees /dev/null, ...
4
votes
2answers
715 views

What process is accessing a mounted filesystem sporadically?

I have a Solaris 10 server with autofs-mounted home dirs. On one server they are not unmounted after the 10 min timeout period. We've got AUTOMOUNT_TIMEOUT=600 in /etc/default/autofs, I ran automount ...
4
votes
2answers
3k views

File descriptor linked to socket or pipe in proc [duplicate]

Possible Duplicate: /proc/PID/fd/X link number i have a question regarding the file descriptors and their linkage in the proc file system. I've observed that if i list the file descriptors ...
4
votes
2answers
177 views

Can I move a directory with open files?

Imagine a bunch of processes using a /home/user/logs directory. They have some logs open for a longer time.
4
votes
2answers
433 views

retrieving names of all open pdf files (in evince or otherwise)

I constantly have many PDF files open. These are usually downloaded using chrome and immediately opened using evince. I sometimes want to persist the state of all my open PDF files, so I could ...
4
votes
1answer
165 views

Using xdg-open for accessing network with normal explorer

I'm working with small network and I want to start network explorer from a terminal. When I tried to type xdg-open network:///server it opened google chrome and did nothing. I also tried to type ...
4
votes
1answer
402 views

Which command will open the default browser on a system to a given web page (terminal)?

Title says it all. Is there a way to open the default browser on a user's system to a specific page from within a Bash script, or other-language script?
4
votes
3answers
1k views

Gedit opening an “Unsaved document” on opening files with mouse

When I open files by double-clicking a file with mouse I always get one additional "Unsaved Document X".. which is very annoying, because I have to close tham all, and click "Close without save" every ...
4
votes
1answer
323 views

How can I configure OpenBox session for opening files by mime type?

I've started using OpenBox and I really like it. But my chromium opens everything with firefox. Is there any fix for that? I'm looking for most lightweight solution, but also with easy and fast ...
3
votes
1answer
95 views

lsof doesn't return files open by the same user

Consider this simple scenario: I open a text file ~/textfile.txt with vim in one terminal (tried with both edit and read-only modes). In a different terminal, I run /usr/sbin/lsof ~/textfile.txt ...
3
votes
2answers
327 views

Capturing new output after deleting the output file

I'm runnig a java server on Debian with this command: java -jar myapp.jar [args] >> log.txt Once I gzipped the log file to send it and then I realized the original file was gone, leaving me ...
3
votes
2answers
74 views

Bizarre Disk Use Problem

I have an external hard drive on which I use rsync to backup my home directory. Today, I tried to umount the drive. It said it was busy. So, I used fuser to figure out who was using it: /media/Panp9 ...
3
votes
1answer
122 views

Efficient mechanism to determine if open file has been externally modified?

For example, the IDE I'm using at the moment (Aptana Studio) notifies me as soon as a file's contents it has open have been changed by some external program. I can imagine having a periodic loop run ...
2
votes
2answers
82 views

File permissions and saving

Let's say you open a file on which you have write permission. Meanwhile you change permissions and remove write permission while you still have the file open in some editor. What will happen if you ...
2
votes
1answer
239 views

How can I access a deleted open file on Linux (output of a running crontab task)?

I have an hourly hour-long crontab job running with some mtr (traceroute) output every 10 minutes (that is going to go for over an hour prior to it being emailed back to me), and I want to see the ...
2
votes
2answers
823 views

File delete versus overwrite and link at /proc/pid/fd

It is well known that UNIX systems won't actually delete a file on disk while the file is in use. So if a file is being accessed by process 1 and process 2 deletes the file using rm, process 1 ...
2
votes
1answer
106 views

vim not shown in fuser

First use Vim to edit a file, say /tmp/A. Assuming that vim process is the only one that accesses /tmp/A, then use "ctrl+z" to suspend the process, and execute fuser /tmp/A Then you see nothing ...
2
votes
1answer
125 views

Max Open Files, clarification needed

On my machine, ulimit -n returns 2560 Given that -n returns The maximum number of open file descriptors. Does it mean that system won't allow more then 2560 open files to be out there at any ...
1
vote
1answer
100 views

If file does not get closed, will OS close it?

If a file is being opened by a process and it is not being closed by any of the processes, will the OS automatically close that open file?