Hi
I am creating 3 background processes in my shell script using &.
I have obtained the 3 PIDs of the background processes using $!.
I need to wait for these to complete and i need the exit status of each of these.
If i use :
wait $PID1
wait $PID2
wait $PID3
and get the exit status of... (1 Reply)
Hi All
Here i have a piece of code,
set filename "./GopiRun.sh"
#I need to wait here until the GopiRun.sh is completed how do i achive this
exit. (1 Reply)
Did not use 'wait' yet.
How I understand by now the wait works only for child processes, started background.
Is there any other way to watch completion of any, not related process (at least, a process, owned by the same user?)
I need to start a background process, witch will be waiting... (2 Replies)
Hello,
I have a script that needs to wait till the previous process is done within the same script.But my script doesnt wait till that it is done.Can anyone suggest how I can stop my process till the previous task is done.
I tried 'wait' but I dont have a static process id so is there... (2 Replies)
Hi,
I am new this forum. I request you peoples help in understanding and finding some solution to my problem.
Here it goes:
I need to perform this set of actions by writing a shell script. I need to read a config file for the bunch of processes to execute.
I need to fecth the pid of... (4 Replies)
Hi all,
I have a shell that kicks off several sub-shells and make them run parallelly, like:
shell1.sh &
shell2.sh &
shell2.sh &
...
However, since all sub-shells run parallely, the parent shell finished right after it's submitted, like:
$ parent.sh &
$ + Done parant.sh &
$
... (2 Replies)
I have the shell script to call a Perl routine and pass the Informatica WorkFlow name to it. Jobs in each group executes in background do not seem to wait at all. How do I make it to WAIT for the prior group to complete before execute the next group of jobs?
Sample of the jobs flow:
{
... (6 Replies)
Hey all,
I want to automate tarring a directory then using ftp to transfer the files over.
I was able to put the commands together but what I'm noticing is that only the very first file is being tarred and then transferred.
tar cvpf new.backup sourceAbove is the command I'm using which works... (4 Replies)
Hi,
I am facing a strange issue,
when i call a script from my while loop in background it doesnt go in background, despite the wait i put below the whil loop it goes forward even before the process put in background is completed.
cat abc.txt | while read -u4 line
do
#if line contains #... (2 Replies)
Hello all,
I have a very basic question. I have a requirement where in, I have a main process which forks a child process, which execs and runs a c executable corresponding to a daemon. In the c executable corresponding to a daemon, as everyone does, I fork another child process, and as part of... (7 Replies)
Discussion started by: sai2krishna
7 Replies
LEARN ABOUT REDHAT
system
SYSTEM(3) Linux Programmer's Manual SYSTEM(3)NAME
system - execute a shell command
SYNOPSIS
#include <stdlib.h>
int system(const char *string);
DESCRIPTION
system() executes a command specified in string by calling /bin/sh -c string, and returns after the command has been completed. During
execution of the command, SIGCHLD will be blocked, and SIGINT and SIGQUIT will be ignored.
RETURN VALUE
The value returned is -1 on error (e.g. fork failed), and the return status of the command otherwise. This latter return status is in the
format specified in wait(2). Thus, the exit code of the command will be WEXITSTATUS(status). In case /bin/sh could not be executed, the
exit status will be that of a command that does exit(127).
If the value of string is NULL, system() returns nonzero if the shell is available, and zero if not.
system() does not affect the wait status of any other children.
CONFORMING TO
ANSI C, POSIX.2, BSD 4.3
NOTES
As mentioned, system() ignores SIGINT and SIGQUIT. This may make programs that call it from a loop uninterruptable, unless they take care
themselves to check the exit status of the child. E.g.
while(something) {
int ret = system("foo");
if (WIFSIGNALED(ret) &&
(WTERMSIG(ret) == SIGINT || WTERMSIG(ret) == SIGQUIT))
break;
}
Do not use system() from a program with suid or sgid privileges, because strange values for some environment variables might be used to
subvert system integrity. Use the exec(3) family of functions instead, but not execlp(3) or execvp(3). system() will not, in fact, work
properly from programs with suid or sgid privileges on systems on which /bin/sh is bash version 2, since bash 2 drops privileges on
startup. (Debian uses a modified bash which does not do this when invoked as sh.)
The check for the availability of /bin/sh is not actually performed; it is always assumed to be available. ISO C specifies the check, but
POSIX.2 specifies that the return shall always be non-zero, since a system without the shell is not conforming, and it is this that is
implemented.
It is possible for the shell command to return 127, so that code is not a sure indication that the execve() call failed.
SEE ALSO sh(1), signal(2), wait(2), exec(3)
2001-09-23 SYSTEM(3)