08-11-2005
The ulimit (-n) is the number of files that can be opened by any single process, not by the system as a whole, so it's for a specific process you need to know this information.
There are several ways to find this information, the easiest being to install lsof and use that. You can however see which filedescriptors are opened by a proceess by looking in the /proc filesystem.
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hello, i need a script (bash type maybe?..), which would check open ports on 127.0.0.1 and then compare open ports with "registered/allowed" port list and try to kill the program who uses unregistered ports. It would be great that script would be started lets say every 5 or 10 minutes.
You see i... (2 Replies)
Discussion started by: MorchiuS
2 Replies
2. Solaris
Hi,
Anyone know the command as how many files are open in Solaris 10 and Linux - i.e. currently open - real time
Thanks (1 Reply)
Discussion started by: civic2005
1 Replies
3. OS X (Apple)
Hi there,
Is there any command to check if a particular application is open on a mac?
thanks
:) (3 Replies)
Discussion started by: davewg
3 Replies
4. Shell Programming and Scripting
Hi Everyone,
# cat a.txt
94,aqqc,62345907,
5,aeec,77,
# cat 1.pl
#!/usr/bin/perl
use strict;
use warnings;
use Date::Manip;
open(my $FA, "/root/a.txt") or die "$!";
while(<$FA>) {
chomp;
my @tmp=split(/\,/, $_);
if (index($tmp, "qq") ne -1) {
... (4 Replies)
Discussion started by: jimmy_y
4 Replies
5. Shell Programming and Scripting
Hi Experts,
I am checking how to get day in Perl.
If it is “Monday” I need to process…below is the pseudo code.
Can you please prove the code for below condition.
if (today=="Monday" )
{
while (current_time LESS THAN 9:01 AM)
... (1 Reply)
Discussion started by: ajaypatil_am
1 Replies
6. UNIX for Dummies Questions & Answers
I am able to connect to a remote host using the legacy IP and port 2222.
Today the remote has a new IP I am unable to connect.
How to check if the remote host is blocking or if its my server is unable to connect.
Err Msg : telnet: Unable to connect to remote host: Connection refused
Err... (5 Replies)
Discussion started by: ITDev01
5 Replies
7. IP Networking
Hello,
please what is the least server resources intensive linux command to veriffy an open proxy works.
I mean one should probably send and receive any data via this proxy? and if data found it returns true
Assuming proxy is 1.2.3.4:1080
I used this:
curl -x $proxy $url... (1 Reply)
Discussion started by: postcd
1 Replies
8. Shell Programming and Scripting
Hello Experts,
I need to write a shell script to check if a file is open and something is being written to it. I want to know how OS handles it. I checked with lsof command but it is not working. For a test I did this.
while true; do echo `date` >>abc.txt; done
then I checked
lsof |... (5 Replies)
Discussion started by: shekhar_4_u
5 Replies
9. Shell Programming and Scripting
Hi. I need to add code to my KSH script to automatically assign an open port number from a pre-defined range to an Oracle listener.
Should I use:
lsof -i
or
netstat -vatn
or something else?
Thanks. (9 Replies)
Discussion started by: user052009
9 Replies
10. UNIX for Beginners Questions & Answers
Hi there! I'm developing a program that allows the user to open and edit files using both an editor and the terminal. Once the user has finished editing the file an update is sent to the logbook that compares the file before and after it was edited - this can only be done if the file is closed (I... (23 Replies)
Discussion started by: cherryTango
23 Replies
FIFO(7) Linux Programmer's Manual FIFO(7)
NAME
fifo - first-in first-out special file, named pipe
DESCRIPTION
A FIFO special file (a named pipe) is similar to a pipe, except that it is accessed as part of the file system. It can be opened by multi-
ple processes for reading or writing. When processes are exchanging data via the FIFO, the kernel passes all data internally without writ-
ing it to the file system. Thus, the FIFO special file has no contents on the file system; the file system entry merely serves as a refer-
ence point so that processes can access the pipe using a name in the file system.
The kernel maintains exactly one pipe object for each FIFO special file that is opened by at least one process. The FIFO must be opened on
both ends (reading and writing) before data can be passed. Normally, opening the FIFO blocks until the other end is opened also.
A process can open a FIFO in nonblocking mode. In this case, opening for read-only will succeed even if no-one has opened on the write
side yet, opening for write-only will fail with ENXIO (no such device or address) unless the other end has already been opened.
Under Linux, opening a FIFO for read and write will succeed both in blocking and nonblocking mode. POSIX leaves this behavior undefined.
This can be used to open a FIFO for writing while there are no readers available. A process that uses both ends of the connection in order
to communicate with itself should be very careful to avoid deadlocks.
NOTES
When a process tries to write to a FIFO that is not opened for read on the other side, the process is sent a SIGPIPE signal.
FIFO special files can be created by mkfifo(3), and are indicated by ls -l with the file type 'p'.
SEE ALSO
mkfifo(1), open(2), pipe(2), sigaction(2), signal(2), socketpair(2), mkfifo(3), pipe(7)
COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-12-03 FIFO(7)