Sponsored Content
Full Discussion: UNIX Pipe
Top Forums UNIX for Dummies Questions & Answers UNIX Pipe Post 86248 by jim mcnamara on Wednesday 12th of October 2005 01:46:32 PM
Old 10-12-2005
a pipe is an intermediate file that allows to separate process to communicate.
The file uses FIFO I/O - first-in first-out. The last thing written to the file is the first thing read from the file.

I don't see any advantage to invoking sqlldr with a pipe. In fact, it may be a problem because pipes have a limit on "record" size - see /usr/include/limits.h _POSIX_PIPE_BUF and PIPE_BUF - and tables with several long columns will cause a problem with overflow.

One way pipes are really useful is to have two separate Oracle sessions comminuicating to one another using DBMS_PIPE
 

10 More Discussions You Might Find Interesting

1. HP-UX

Compress while wrting to a file using a unix pipe

I would like to know if the following can be done. route output from an sql select directly to a pipe and compress it at the same time. regards Albert (2 Replies)
Discussion started by: booyena1
2 Replies

2. Programming

unix pipe in C

I currently stuck on a simple program that requires unix pipe. I'm have never programmed with unix pipe before, so if anyone can point me to the right different will be greatly appreciated! I'm suppose to write a program that the parent spawns many child processes and each of the child process... (1 Reply)
Discussion started by: meh
1 Replies

3. Shell Programming and Scripting

splitting a pipe delimited file in unix

Could one of you shad some light on this: I need to split the file by determining the record count and than splitting it up into 4 files. Please note, this is not a fixed record length but rather a "|" delimited file. I am not sure as how to handle reminder/offset for the 4th file. For... (4 Replies)
Discussion started by: ddedic
4 Replies

4. UNIX for Dummies Questions & Answers

Definition for the UNIX term Pipe

Looking for examples/definition of what the term Pipe means in UNIX. Please provide answers and illustrations if possible or direction. Thanks!:) (5 Replies)
Discussion started by: dfrost126
5 Replies

5. UNIX for Advanced & Expert Users

unix command pipe

I am pretty new to UNIX. My client has a requirement where in a directory we have some files with somewhat similar name like test_XX.txt, test_XY.txt, test_XZ.txt, test_ZZ.txt, test_ZY.txt, test_ZX.txt, test_YY.txt......Out of these files few files have 0 bytes. Is there a way where we can go... (7 Replies)
Discussion started by: RubinPat
7 Replies

6. Shell Programming and Scripting

Converting hex value 7C (for pipe) to CRLF in Unix

I am trying to convert a txt file that includes one long string of data. The lines are separated with hex value 7C (for pipe). I am trying to process this file using SQR (Peoplesoft) so I thought the easiest thing to do would be to replace the eol char with a CRLF in unix so I can just... (4 Replies)
Discussion started by: sfedak
4 Replies

7. UNIX for Dummies Questions & Answers

Passing struct through unix pipe -solved

EDIT: Nevermind, called a friend who is good at this stuff and he figured it out :D Hi all, So I'm trying to teach myself to write programs for unix in c. I am currently creating a program, and I need to pass a struct through a pipe, but I can't figure out how. The struct I want to pass... (0 Replies)
Discussion started by: twnsfn34
0 Replies

8. Shell Programming and Scripting

Replacing UNIX 1 byte delimiters to the pipe separator

Hi I am new to Unix Shell scripting have a requirement where I have to replace the "unix 1 byte delimiter" with the "pipe" separator and also remove any carriage returns and line feeds if any The Source File 4 QFH Jungle Hill 32-34 City Road London SE23 3UX the output should be ... (3 Replies)
Discussion started by: dJHa
3 Replies

9. Shell Programming and Scripting

UNIX fifo concurrent read from a named pipe

I have created a fifo named pipe in solaris, which writes the content of a file, line by line, into pipe as below: $ mkfifo namepipe $ cat books.txt "how to write unix code" "how to write oracle code" $ cat books.txt >> namepipe & I have a readpipe.sh script which reads the named... (2 Replies)
Discussion started by: naveen mani
2 Replies

10. UNIX for Beginners Questions & Answers

UNIX Pipe -Exit when there are no bytes to read

Hi All, I'm creating a program which reads millions of bytes from the PIPE and do some processing. As the data is more, the idea is to read the pipe parallely. Sun Solaris 8 See the code below: #!/bin/sh MAXTHREAD=30 awk '{print $1}' metadata.csv > nvpipe & while do ... (3 Replies)
Discussion started by: mr_manii
3 Replies
pipe(2) 							   System Calls 							   pipe(2)

NAME
pipe - create an interprocess channel SYNOPSIS
#include <unistd.h> int pipe(int fildes[2]); DESCRIPTION
The pipe() function creates an I/O mechanism called a pipe and returns two file descriptors, fildes[0] and fildes[1]. The files associated with fildes[0] and fildes[1] are streams and are both opened for reading and writing. The O_NDELAY, O_NONBLOCK, and FD_CLOEXEC flags are cleared on both file descriptors. The fcntl(2) function can be used to set these flags. A read from fildes[0] accesses the data written to fildes[1] on a first-in-first-out (FIFO) basis and a read from fildes[1] accesses the data written to fildes[0] also on a FIFO basis. Upon successful completion pipe() marks for update the st_atime, st_ctime, and st_mtime fields of the pipe. RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The pipe() function will fail if: EMFILE More than {OPEN_MAX} file descriptors are already in use by this process. ENFILE The number of simultaneously open files in the system would exceed a system-imposed limit. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Async-Signal-Safe | +-----------------------------+-----------------------------+ SEE ALSO
sh(1), fcntl(2), fstat(2), getmsg(2), poll(2), putmsg(2), read(2), write(2), attributes(5), standards(5), streamio(7I) NOTES
Since a pipe is bi-directional, there are two separate flows of data. Therefore, the size (st_size) returned by a call to fstat(2) with argument fildes[0] or fildes[1] is the number of bytes available for reading from fildes[0] or fildes[1] respectively. Previously, the size (st_size) returned by a call to fstat() with argument fildes[1] (the write-end) was the number of bytes available for reading from fildes[0] (the read-end). SunOS 5.11 23 Apr 2002 pipe(2)
All times are GMT -4. The time now is 03:01 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy