11-18-2008
Joey -
Homework and classwork are not allowed on the Forums. Sorry. Thread closed.
7 More Discussions You Might Find Interesting
1. Programming
Would anyone be so kind to explain to me the function of dup() in UNIX? As far as I am concerned, it duplicates a file descriptor. Under what circumstances would we need to duplicate a file descriptor in a UNIX environment?
Thank you.
vinchen (3 Replies)
Discussion started by: vinchen
3 Replies
2. Programming
I have met this code:
switch(fork()) {
case 0:
close(1);
dup(p);
close(p);
close(p);
execvp(<whatever>);
perror("Exec failed");
}
Can anyone tell me what this piece of code does?
Thx alot.. (1 Reply)
Discussion started by: AkumaTay
1 Replies
3. Programming
I'm having difficulty understanding the purposes of using dup/dup2 when involving forks.
for example, if we call fork() once, that is, we are creating a child process. In what cases would we need to use dup or dup2 to duplicate the file descriptors for standard output and standard error? What... (1 Reply)
Discussion started by: Yifan_Guo
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4. Red Hat
Ntop is running on redhat. But It gives DUP! error while pinging to any places
I dont know why DUP! error is occured.
# ping google.com
PING google.com (74.125.39.147) 56(84) bytes of data.
64 bytes from fx-in-f147.1e100.net (74.125.39.147): icmp_seq=1 ttl=44 time=54.1 ms
64 bytes from... (6 Replies)
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5. Shell Programming and Scripting
Hi,
I have a requirement where I have to identify duplicates from a file based on the first 6 chars (It is fixed width file of 12 chars length) and whenever a duplicate row is found, its original and duplicate row's last 2 chars should be updated to all 0's if they are not same. (I mean last 2... (3 Replies)
Discussion started by: farawaydsky
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6. Shell Programming and Scripting
Hi Gurus,
I need to count the duplicate records in file
file
abc
abc
def
ghi
ghi
jkl
I want to get below result:
abc ,2
abc, 2
def ,1
ghi ,2
ghi, 2
jkl ,1
or
abc ,2
def ,1 (3 Replies)
Discussion started by: ken6503
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7. UNIX and Linux Applications
The problematic directory is the following:
/root/.cache/deja-dup
This directory grows until my "/" is full and then the restoring activity fails.
I already tried to create a symbolic link with origin another partition where I have more space. However during the restoring activity ... (4 Replies)
Discussion started by: puertas12
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dup(2) System Calls Manual dup(2)
NAME
dup - duplicate an open file descriptor
SYNOPSIS
DESCRIPTION
fildes is a file descriptor obtained from a or system call. returns a new file descriptor having the following in common with the origi-
nal:
o Same open file (or pipe).
o Same file pointer (i.e., both file descriptors share one file pointer).
o Same access mode (read, write or read/write).
o Same file status flags (see fcntl(2),
The new file descriptor is set to remain open across system calls. See fcntl(2).
The file descriptor returned is the lowest one available.
RETURN VALUE
Upon successful completion, the file descriptor is returned as a non-negative integer. Otherwise, a value of -1 is returned and is set to
indicate the error.
ERRORS
fails if one or more of the following is true:
fildes is not a valid open file descriptor.
Request violates the maximum number of open file descriptors.
AUTHOR
was developed by AT&T and HP.
SEE ALSO
close(2), creat(2), dup2(2), exec(2), fcntl(2), open(2), pipe(2), privileges(5).
STANDARDS CONFORMANCE
dup(2)