I don't think the "resethand" issue is related. Your shell has no issue receiving the interrupt, and does exactly what you told it to do -- wait for input. What needs to be told that something is happening is read. How can you do that? Close whatever it's reading from. Killing tail would do it, for example. Or using a named pipe and forcing it to close.
Hi,
Could someone please tell me how to wakeup sleeping processes? (i.e. change the process status from "S" to "R" when viewing in ps command).
I ran a few programs in the background by "&" which went into "sleep" mode and I want them to run.
Any help will be greatly appreciated.
Steve (11 Replies)
Hi all,
Can anybody send the autosys developer sample resumes.
If this is not the correct place to ask please let me know where can I get them.
Your help would be appreciated.
Thanks
Renuka (0 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)
Hi
Is there any way to find out in a single step ( command) the step where the pipe command failed when using multiple commands using pipe .
eg : ll *.tar | grep dec | grep december.tar
the first step is listing all tar files . Second step constitutes piping that data and
doing grep... (5 Replies)
I had a script executing every hour to kill a process. I used loop rather than cron to execute it periodically. But now when I am trying to kill that sleep process of 1 hour its not getting killed. it is taking a new PID everytime I kill. To disable the script commenting is the only option... (1 Reply)
Dear shell experts,
I spent last few days porting ksh script from ksh88/SunOS to ksh93/Linux.
Basically, things are going well and I do not have too much troubles porting ks88 script to ksh93, but I stuck on one item. It's about sending and handling the signal.
I found two similar... (8 Replies)
Discussion started by: bzk
8 Replies
LEARN ABOUT LINUX
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 /* See feature_test_macros(7) */
#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 3.27 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 2010-09-10 PIPE(2)