Hi
I tried to open the man page of sh and piped to `pg`. Normally while reading a file page by page using `pg`, if we wanna quit at the middle of file, we give "q" near the colon mode.
Ex1: $cat file1 | pg
hi
how
r
u
: (page1) now press "return key", it will go to next page
yes
i ... (1 Reply)
Hi
I tried to open the man page of sh and piped to `pg`. Normally while reading a file page by page using `pg`, if we wanna quit at the middle of file, we give "q" near the colon mode.
Ex1: $cat file1 | pg
hi
how
r
u
: (page1) now press "return key", it will go to next page
yes
i ... (3 Replies)
hi guys, o have a big error
in this program but i cant solve
someone ?!
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
int main(int argc, char *argv){
int cont = 2, posicao;
char geraArquivo= "|cat>>", espaco=" ";
char nomeArquivo, comando,... (11 Replies)
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)
I want to do the following in perl:
print $output | grep ' something' | awk '{print $2}';
I know there is system(); but it does not behave the way I was expecting it in perl. (2 Replies)
Hi guys.
I've a problem with pipes, I'm trying to make a program that can create a child process and they must generate the folowing output:
Ping ... Pong
Ping ... Pong
Ping ... Pong
I want syncronize the output whithout using the semephores, can anyone help me?
Thanks in advance.
/**
*... (1 Reply)
Hi all,
I would like to use properly an input pipe, like this :
cat myFile.txt | myCommand.shI always find this solution :
while read line; do ...; donebut I have a great lost of performance !
On a big file, with a simple grep, I can spend 2400 times more time ! oO
(from 0,023sec to 1m)... (4 Replies)
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)
Discussion started by: rohit_shinez
13 Replies
LEARN ABOUT SUSE
pipe2
PIPE(2) Linux Programmer's Manual PIPE(2)NAME
pipe, pipe2 - create pipe
SYNOPSIS
#include <unistd.h>
int pipe(int pipefd[2]);
#define _GNU_SOURCE
#include <unistd.h>
int pipe2(int pipefd[2], int flags);
DESCRIPTION
pipe() creates a pipe, a unidirectional data channel that can be used for interprocess communication. The array pipefd is used to return
two file descriptors referring to the ends of the pipe. pipefd[0] refers to the read end of the pipe. pipefd[1] refers to the write end
of the pipe. Data written to the write end of the pipe is buffered by the kernel until it is read from the read end of the pipe. For fur-
ther details, see pipe(7).
If flags is 0, then pipe2() is the same as pipe(). The following values can be bitwise ORed in flags to obtain different behavior:
O_NONBLOCK Set the O_NONBLOCK file status flag on the two new open file descriptions. Using this flag saves extra calls to fcntl(2) to
achieve the same result.
O_CLOEXEC Set the close-on-exec (FD_CLOEXEC) flag on the two new file descriptors. See the description of the same flag in open(2) for
reasons why this may be useful.
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
ERRORS
EFAULT pipefd is not valid.
EINVAL (pipe2()) Invalid value in flags.
EMFILE Too many file descriptors are in use by the process.
ENFILE The system limit on the total number of open files has been reached.
VERSIONS
pipe2() was added to Linux in version 2.6.27; glibc support is available starting with version 2.9.
CONFORMING TO
pipe(): POSIX.1-2001.
pipe2() is Linux-specific.
EXAMPLE
The following program creates a pipe, and then fork(2)s to create a child process; the child inherits a duplicate set of file descriptors
that refer to the same pipe. After the fork(2), each process closes the descriptors that it doesn't need for the pipe (see pipe(7)). The
parent then writes the string contained in the program's command-line argument to the pipe, and the child reads this string a byte at a
time from the pipe and echoes it on standard output.
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
int
main(int argc, char *argv[])
{
int pipefd[2];
pid_t cpid;
char buf;
if (argc != 2) {
fprintf(stderr, "Usage: %s <string>
", argv[0]);
exit(EXIT_FAILURE);
}
if (pipe(pipefd) == -1) {
perror("pipe");
exit(EXIT_FAILURE);
}
cpid = fork();
if (cpid == -1) {
perror("fork");
exit(EXIT_FAILURE);
}
if (cpid == 0) { /* Child reads from pipe */
close(pipefd[1]); /* Close unused write end */
while (read(pipefd[0], &buf, 1) > 0)
write(STDOUT_FILENO, &buf, 1);
write(STDOUT_FILENO, "
", 1);
close(pipefd[0]);
_exit(EXIT_SUCCESS);
} else { /* Parent writes argv[1] to pipe */
close(pipefd[0]); /* Close unused read end */
write(pipefd[1], argv[1], strlen(argv[1]));
close(pipefd[1]); /* Reader will see EOF */
wait(NULL); /* Wait for child */
exit(EXIT_SUCCESS);
}
}
SEE ALSO fork(2), read(2), socketpair(2), write(2), popen(3), pipe(7)COLOPHON
This page is part of release 3.25 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2009-09-15 PIPE(2)