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Full Discussion: Doubt about pipes and subprocess
Top Forums Shell Programming and Scripting Doubt about pipes and subprocess Post 302388832 by Andre_Merzky on Thursday 21st of January 2010 02:58:15 PM
Old 01-21-2010
Hope this helps:

Code:
bash-3.2$ cat getppid.c 

#include <stdio.h>
#include <unistd.h>

int main ()
{
  fprintf (stdout, "%d\n", getppid ());
  return 0;
}

bash-3.2$ make getppid
cc     getppid.c   -o getppid

bash-3.2$ ./getppid >> t |  ( ./getppid >> t ; ./getppid >> t ) ; cat t
14236
14774
14774

I assume you talk about bash - tcsh is different here:

Code:
tcsh $  ( ./getppid ; ./getppid )
14867
12872

Last edited by Andre_Merzky; 01-21-2010 at 03:59 PM.. Reason: Who needs preview if you can edit ;-)
 

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LEARN ABOUT DEBIAN

getppid

GETPID(2)						      BSD System Calls Manual							 GETPID(2)

NAME

     getpid, getppid -- get parent or calling process identification

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/types.h>
     #include <unistd.h>

     pid_t
     getpid(void);

     pid_t
     getppid(void);

DESCRIPTION

     The getpid() system call returns the process ID of the calling process.  Though the ID is guaranteed to be unique, it should NOT be used for
     constructing temporary file names, for security reasons; see mkstemp(3) instead.

     The getppid() system call returns the process ID of the parent of the calling process.

ERRORS

     The getpid() and getppid() system calls are always successful, and no return value is reserved to indicate an error.

SEE ALSO

     fork(2), getpgrp(2), kill(2), setpgid(2), setsid(2), exec(3)

STANDARDS

     The getpid() and getppid() system calls are expected to conform to ISO/IEC 9945-1:1990 (``POSIX.1'').

HISTORY

     The getpid() function appeared in Version 7 AT&T UNIX.

BSD
								 November 2, 2006							       BSD
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