Pipes and fifos cannot overflow.
...
With one process reading from a pipe and another writing to a pipe, they will take turns running.
In fact, this sort of mechanism works very well when having to export Oracle data when the data exceeds 2 GB and the Oracle exp utility doesn't support large filesystems.
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)
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)
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)
Looking for examples/definition of what the term Pipe means in UNIX. Please provide answers and illustrations if possible or direction. Thanks!:) (5 Replies)
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)
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)
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)
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)
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)
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
LEARN ABOUT BSD
pipe
PIPE(2) System Calls Manual PIPE(2)NAME
pipe - create an interprocess communication channel
SYNOPSIS
pipe(fildes)
int fildes[2];
DESCRIPTION
The pipe system call creates an I/O mechanism called a pipe. The file descriptors returned can be used in read and write operations. When
the pipe is written using the descriptor fildes[1] up to 4096 bytes of data are buffered before the writing process is suspended. A read
using the descriptor fildes[0] will pick up the data.
It is assumed that after the pipe has been set up, two (or more) cooperating processes (created by subsequent fork calls) will pass data
through the pipe with read and write calls.
The shell has a syntax to set up a linear array of processes connected by pipes.
Read calls on an empty pipe (no buffered data) with only one end (all write file descriptors closed) returns an end-of-file.
Pipes are really a special case of the socketpair(2) call and, in fact, are implemented as such in the system.
A signal is generated if a write on a pipe with only one end is attempted.
RETURN VALUE
The function value zero is returned if the pipe was created; -1 if an error occurred.
ERRORS
The pipe call will fail if:
[EMFILE] Too many descriptors are active.
[ENFILE] The system file table is full.
[EFAULT] The fildes buffer is in an invalid area of the process's address space.
SEE ALSO sh(1), read(2), write(2), fork(2), socketpair(2)BUGS
Should more than 4096 bytes be necessary in any pipe among a loop of processes, deadlock will occur.
4th Berkeley Distribution August 26, 1985 PIPE(2)