10-14-2004
File Descriptor Help
What is a file descriptor in Unix??
How to find a file descriptor of a file in Unix??
Does it have anything to do with the Inode numbers??
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
I am trying to find a way to check the current status of a file. Such as some cron job processes are dependent on the completion of others. if a file is currently being accessed / modified or simply open state I will wait until it is done being processed before attempting the next process on that... (3 Replies)
Discussion started by: Gary Dunn
3 Replies
2. UNIX for Advanced & Expert Users
Im working on writing a small operating system. I am currently working on implementing dup, dup2, pipe, and close and I need to implement some type of file descriptor table in my PCB.
I was wondering if there is anyone who is familiar with linux/unix implementation of these tables who could... (6 Replies)
Discussion started by: Ashaman0
6 Replies
3. Shell Programming and Scripting
I am trying to right a function which uses a file descriptor to write to a log file. The problem is that the on the print statement the file descriptor is called bad. Now when I first open the file and print to it in the f_open function by passing the descriptor to f_print_log all works well,... (6 Replies)
Discussion started by: robotball
6 Replies
4. Shell Programming and Scripting
Hello All,
Im opening a file desciptor in perl and sending data using print CMD "$xyz".
is there a limit to the length of the string that I can give to this CMD at a time. (3 Replies)
Discussion started by: rimser9
3 Replies
5. UNIX for Dummies Questions & Answers
Hi
What the below path contains?
/proc/<pid>/fd (1 Reply)
Discussion started by: siba.s.nayak
1 Replies
6. Shell Programming and Scripting
Hello,
How can i use file descriptor in a script to read 2 files at the same time and extract line 200 from file 1 and line 500 from file 2.
Thanks. (6 Replies)
Discussion started by: LiorAmitai
6 Replies
7. Shell Programming and Scripting
I am trying to write a script which will only show me the file descriptor count for a process/pid. My script will return me the count only not the whole output. For example, I would like my script to return the output 23 this case, not the whole output.
Can anybody please help me how do I get... (11 Replies)
Discussion started by: mohullah
11 Replies
8. Shell Programming and Scripting
Hi,
I am trying to read a file line-by-line in a while loop, and perform some tasks which involves non-interactive SSH to a remote server. The code looks something like this --
#!/usr/bin/ksh
export myFile=/path/to/my/file.load
while read line
do
do something
## Adding the SSH... (2 Replies)
Discussion started by: Subu1987
2 Replies
9. Shell Programming and Scripting
Greetings.
I am happily using constructs like the following; I have set -x to show fine distinctions.
$ exec 4> afile
+ exec
+ 4> afile
$ print -u4 This is the first line in afileAs you can see from the -x expansion, the shell performed the exec command and redirected file descriptor to... (4 Replies)
Discussion started by: rpaskudniak
4 Replies
10. Shell Programming and Scripting
hello,
Someone can help me with redirectors?
I am writing this script in bash enviroment on Fedora:
exec 4<> /dev/tcp/10.10.11.30/5000 #open socket in input/output
strings<&4 >file.txt &
I send file descriptor 4 to string command to purge data stream from special char while come from... (3 Replies)
Discussion started by: rattoeur
3 Replies
LEARN ABOUT LINUX
posix_openpt
POSIX_OPENPT(3) Linux Programmer's Manual POSIX_OPENPT(3)
NAME
posix_openpt - open a pseudo-terminal device
SYNOPSIS
#include <stdlib.h>
#include <fcntl.h>
int posix_openpt(int flags);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
posix_openpt(): _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600
DESCRIPTION
The posix_openpt() function opens an unused pseudo-terminal master device, returning a file descriptor that can be used to refer to that
device.
The flags argument is a bit mask that ORs together zero or more of the following flags:
O_RDWR Open the device for both reading and writing. It is usual to specify this flag.
O_NOCTTY
Do not make this device the controlling terminal for the process.
RETURN VALUE
On success, posix_openpt() returns a nonnegative file descriptor which is the lowest numbered unused descriptor. On failure, -1 is
returned, and errno is set to indicate the error.
ERRORS
See open(2).
VERSIONS
Glibc support for posix_openpt() has been provided since version 2.2.1.
CONFORMING TO
posix_openpt() is part of the Unix98 pseudo-terminal support (see pts(4)). This function is specified in POSIX.1-2001.
NOTES
This function is a recent invention in POSIX. Some Unix implementations that support System V (aka Unix 98) pseudo-terminals don't have
this function, but it is easy to implement:
int
posix_openpt(int flags)
{
return open("/dev/ptmx", flags);
}
SEE ALSO
open(2), getpt(3), grantpt(3), ptsname(3), unlockpt(3), pts(4), pty(7)
COLOPHON
This page is part of release 3.27 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/.
2007-07-26 POSIX_OPENPT(3)