08-13-2010
A file descriptor is an index in a per process table. It isn't predefined outside 0, 1 and 2 which are stdin, stdout and stderr when the process starts.
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 Dummies Questions & Answers
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?? (3 Replies)
Discussion started by: rahulrathod
3 Replies
3. UNIX for Dummies Questions & Answers
Hi everybody,
i am newbie to unix and confused with file pointers and file descripters.
could anyone help me to clear my doubts ..
when we call unix system calls to create a file then we are dealing wih file descripters
i think file descripters are also normals file as stored inhard disks... (1 Reply)
Discussion started by: johnray31
1 Replies
4. Programming
Hi,
I want to validate that a file is a socket file on Linux. I know I can do this using the S_ISSOCK macro, but I am not sure how to get the file descriptor for the socket file.
For example, I know that /tmp/mapping-foo is a socket file. In Python I can do something like this:
>>> import... (2 Replies)
Discussion started by: goon12
2 Replies
5. 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
6. UNIX for Dummies Questions & Answers
Hi
What the below path contains?
/proc/<pid>/fd (1 Reply)
Discussion started by: siba.s.nayak
1 Replies
7. Programming
Hi ,
i have two basic requirement on linux platform . I am using C language to do this .
1) copying one file to another (assuming i know their file descriptors)
2) Overwriting a file using it file descriptor .
Please guide.
regards
Aki (2 Replies)
Discussion started by: meet123321
2 Replies
8. 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
9. 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
10. 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
LEARN ABOUT DEBIAN
stderr
FD(4) BSD Kernel Interfaces Manual FD(4)
NAME
fd, stdin, stdout, stderr -- file descriptor files
DESCRIPTION
The files /dev/fd/0 through /dev/fd/# refer to file descriptors which can be accessed through the file system. If the file descriptor is
open and the mode the file is being opened with is a subset of the mode of the existing descriptor, the call:
fd = open("/dev/fd/0", mode);
and the call:
fd = fcntl(0, F_DUPFD, 0);
are equivalent.
Opening the files /dev/stdin, /dev/stdout and /dev/stderr is equivalent to the following calls:
fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
fd = fcntl(STDOUT_FILENO, F_DUPFD, 0);
fd = fcntl(STDERR_FILENO, F_DUPFD, 0);
Flags to the open(2) call other than O_RDONLY, O_WRONLY and O_RDWR are ignored.
IMPLEMENTATION NOTES
By default, /dev/fd is provided by devfs(5), which provides nodes for the first three file descriptors. Some sites may require nodes for
additional file descriptors; these can be made available by mounting fdescfs(5) on /dev/fd.
FILES
/dev/fd/#
/dev/stdin
/dev/stdout
/dev/stderr
SEE ALSO
tty(4), devfs(5), fdescfs(5)
BSD
June 9, 1993 BSD