I have encountered a strange problem dealing with pipes
and forking. The program basicaly does this:
cat file | tbl | eqn | groff
Now, I have a parent process that forks children
that that exec the stuff that they should. The pipes defined
in the parent are the ones used.
The chain goes... (1 Reply)
I use read often in scripts to filter the right part into a variable like:
$ print "abc cde efg" | read k l ; print "k=$k, l=$l"
k=, l=
This works on linux and unix versions I work with. On OSX 10.4 this
doesn't work. I found a workaround but would like to know
why the original line... (5 Replies)
Basically I am trying to write a short script to report total space used on /u0? file systems. This is what I was trying to do:df -k /u0? | grep -v kbytes | awk '{ printf $2 "+" }' | sed s/.$// | bcBut it returns no output.
This works however: > A=`df -k /u0? |grep -v kbytes | awk '{ printf $2... (2 Replies)
Is there a way to know whether is pipe is opened in read or write mode.I mean is there any signal that is generated when a pipe is opened in read or write mode.
If you have some solution .please let me know ........ (2 Replies)
Hello everyone
I got a school project that was due yesterday so i really would aprreciate some help
the following is an example of the input file (bateriaTestes)
1 caeiro 2000 d
2 pessoa 100 w
3 campos 200 b
4 soares 500 w
simple 4 field lines. lines separated by \n and fields by... (1 Reply)
Hi,
Can any one please help me with this. Am struggling hard to get a solution.
I am doing telnet through a C program and getting the stdout file descriptor of the remote machine to pipe.
read() function is getting data, But whenl it receives SOH character ie. ^A ( Start of heading = Console... (2 Replies)
Could anyone tell me whats wrong whit this piping? the commands that they execute are correct. the command I am trying is ls|wc. Both processes go to the right if statement.
for(i=0;i<argc;i++){
if(i==0&&argc>1){//first command
if(pipe(pipa1)==-1)
... (2 Replies)
Hello !
I want to process a text file in order to extract desired data using sed and grep... Now I am facing a problem piping to grep... nothing happens..
The text consists of blocks of 3 lines that may (or not) contain the Desired data.
the desired data is on each 2... (4 Replies)
hi i am having issues with extra pipe.
i have a data file and i need to remove the extra pipe in the(example 4th and 7thline) in datafile. there are many other line and filed like this which i need to remove from files. The sample data is below:
270 31|455004|24/03/2010|0001235|72
271... (3 Replies)
Hi all,
Im trying to do a simple program which ask the user for a unix command with the arguments. The program fork and the two process communicate with pipes. The child process call execvp with the command and the father process read the result of the execvp via the pipe.
This program works... (11 Replies)
Discussion started by: blackmamba21
11 Replies
LEARN ABOUT DEBIAN
explain_pipe_or_die
explain_pipe_or_die(3) Library Functions Manual explain_pipe_or_die(3)NAME
explain_pipe_or_die - create pipe and report errors
SYNOPSIS
#include <libexplain/pipe.h>
void explain_pipe_or_die(int *pipefd);
DESCRIPTION
The explain_pipe_or_die function is used to call the pipe(2) system call. On failure an explanation will be printed to stderr, obtained
from explain_pipe(3), and then the process terminates by calling exit(EXIT_FAILURE).
This function is intended to be used in a fashion similar to the following example:
explain_pipe_or_die(pipefd);
pipefd The pipefd, exactly as to be passed to the pipe(2) system call.
Returns:
This function only returns on success. On failure, prints an explanation and exits.
SEE ALSO pipe(2) create pipe
explain_pipe(3)
explain pipe(2) errors
exit(2) terminate the calling process
COPYRIGHT
libexplain version 0.52
Copyright (C) 2009 Peter Miller
explain_pipe_or_die(3)