i made a lot of processes. here is the code:
main()
{
printf("\nEnter K="); scanf("%d",&k);
printf("Enter L="); scanf("%d",&l);
printf("\nFather id=%d\n",getpid());
x=0;
makechild();
sleep(2);
return 1;
}
int makechild()
{
for(q=1;q<=k;q++)
{
if(f=fork())
{
... (5 Replies)
Hi,
Is it possible that the output of a command is piped into a unix function? Just like in below:
#!/bin/ksh
concat(){
echo Orbix
}
echo "Hello there" | concat
How to manipulate the output of a command inside the function? (2 Replies)
We encountered an issue in our project while using the Interix UNIX (SFU 3.5) and explained our query below. We would be happy if anybody helps us to troubleshoot the problem J
In our code the trapping signal for all signals like HUP, INT, QUIT, ILL, TRAP, ABRT, EXCEPT, etc., is initialized in... (4 Replies)
Hello,
Would this be an acceptable way of creating a non-blocking pipe.
Basically I want to create kind of a server client arch.
This code would be in the server, and I don't want to have to wait for
clients to read before moving on to the next client. One problem I
can see is if... (4 Replies)
I have the following command in a Bash shell script:
who | grep -w $1 | some other commands
If grep fails, an error message is displayed. How do I test if grep fails and still be able to pipe it's output to the rest of the commands?
I have the following solution:
a=`who | grep -w $1`... (3 Replies)
Hello guys,
my professor give me 2 days to study and make a program usign pipe, fork in c
i need to do a program
read a arq.txt
the father process read the file and the child print !
like this
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
int main (){
... (1 Reply)
Hi, guys:
I am working on my shell using c. How can I use pipe to implement the following?
ls -l 1>> | grep hellp 1<< 2>> | less 2<<
(the output of ls goes to grep, and the output of grep goes to less)
Thanks
Please use and tags when posting code, data or logs etc. to preserve... (1 Reply)
Hi guys,
I need to know how i can ignore Pipe '|' if Pipe is coming as a column in Pipe delimited file
for eg:
file 1:
xx|yy|"xyz|zzz"|zzz|12...
using below awk command
awk 'BEGIN {FS=OFS="|" } print $3
i would get xyz
But i want as :
xyz|zzz to consider as whole column... (13 Replies)
Greetings. This is my first post in this forum; I hope y'all find it useful. One caveat: "Concise" is my middle name. NOT! :D
I am almost done with a shell script that runs as a daemon. It monitors a message log that is frequently written to by a database server but it it works my client will... (2 Replies)
Discussion started by: jakesalomon
2 Replies
LEARN ABOUT MOJAVE
pipe
PIPE(2) BSD System Calls Manual PIPE(2)NAME
pipe -- create descriptor pair for interprocess communication
SYNOPSIS
#include <unistd.h>
int
pipe(int fildes[2]);
DESCRIPTION
The pipe() function creates a pipe (an object that allows unidirectional data flow) and allocates a pair of file descriptors. The first
descriptor connects to the read end of the pipe; the second connects to the write end.
Data written to fildes[1] appears on (i.e., can be read from) fildes[0]. This allows the output of one program to be sent to another pro-
gram: the source's standard output is set up to be the write end of the pipe; the sink's standard input is set up to be the read end of the
pipe. The pipe itself persists until all of its associated descriptors are closed.
A pipe whose read or write end has been closed is considered widowed. Writing on such a pipe causes the writing process to receive a SIGPIPE
signal. Widowing a pipe is the only way to deliver end-of-file to a reader: after the reader consumes any buffered data, reading a widowed
pipe returns a zero count.
The generation of the SIGPIPE signal can be suppressed using the F_SETNOSIGPIPE fcntl command.
RETURN VALUES
On successful creation of the pipe, zero is returned. Otherwise, a value of -1 is returned and the variable errno set to indicate the error.
ERRORS
The pipe() call will fail if:
[EFAULT] The fildes buffer is in an invalid area of the process's address space.
[EMFILE] Too many descriptors are active.
[ENFILE] The system file table is full.
SEE ALSO sh(1), fork(2), read(2), socketpair(2), fcntl(2), write(2)HISTORY
A pipe() function call appeared in Version 6 AT&T UNIX.
4th Berkeley Distribution February 17, 2011 4th Berkeley Distribution