The parent application can set up standard output of the shell script to be the write end of a pipe that the parent can use to read status from the child.
The parent can create a named pipe (or regular file) and pass the name of that file to the shell script as an operand. The child can then write status to that file and the parent can read status from that file.
The parent can set up a signal catching function for a signal and pass its process ID to the child shell script. The child can then use:
to notify the parent that some milestone has been reached.
Use your imagination... There are lots of ways for one process to talk to another process.
This User Gave Thanks to Don Cragun For This Post:
AIX 4.3.3
I am trying to write a signal handler into a ksh shell script. I would like to capture the SIGTERM, SIGINT, and the SIGTSTP signals, print out a message to the terminal, and continue executing the script. I have found a way to block the signals:
#! /bin/ksh
SIGTERM=15
SIGINT=2... (2 Replies)
Helo,
I want to write shell script which takes back of all binaries (exe files).
and when i uninstall the upgraded system which automatically restore the old binary which we have take as back up.
can u tell me how to write such shell scripts.
Regards,
Amit (5 Replies)
I need to write a c program that uses the fork and excel system calls to run the shell script mode invoked like this: "./mode 644 ls -l" (that is the argumetns will always be 644 ls -l)
here's the mode script:
#!/bin/sh
octal="$1"
shift
find . -maxdepth 1 -perm $octal -exec $@ {} \;
... (3 Replies)
Hi ,
I do have a shell which test the connectivity using ssh, soon after the login it should use the keys Ctrl + z or Ctrl + c to exit from login promt. So how do i need to implement these . (3 Replies)
Hi ,
i have a scenario where...i have to put a check where if script is executing more than 15mins i have to kill that script and n retry again 2nd time.
i this case i can use background process to do it but i feel trap will be the efficent way to do so...
but i dont know much about it... (1 Reply)
When command is executed by forking, the console displays the status of that command. I want to suppress it.. how to do it ?
Example:
var1=`date` &
echo "hello world";
output:
hello world
+ Done var1=`date`
I want to suppress the second line "+ Done var1=`date`".
I... (10 Replies)
Hi, I'm writing a shell script where I want to call fork(). However I wrote like this "var=fork()" in c style and got this error:
"syntax error near unexpected token `(' "
How could I call fork() in shell script? Thanks in advance.
Duplicate Post - Continue Here - Please Do Not Cross Post... (0 Replies)
Hi, I'm writing a shell script where I want to call fork(). However I wrote like this "var=fork()" in c style and got this error:
"syntax error near unexpected token `(' "
How could I call fork() in shell script? Thanks in advance. (2 Replies)
Hi All,
I have a shell script(test_abc.sh) with the following shell commands, which are invoking the same shell script with different parameters.
test_abc.sh
. ./test.sh abc >> test.log
. ./test.sh xyz >> test.log
. ./test.sh pys >> test.log
. ./test.sh abc >> test.log
.
.
... (4 Replies)
Discussion started by: dev.devil.1983
4 Replies
LEARN ABOUT DEBIAN
preap
preap(1) User Commands preap(1)NAME
preap - force a defunct process to be reaped by its parent
SYNOPSIS
preap [-F] pid...
DESCRIPTION
A defunct (or zombie) process is one whose exit status has yet to be reaped by its parent. The exit status is reaped via the wait(3C),
waitid(2), or waitpid(3C) system call. In the normal course of system operation, zombies may occur, but are typically short-lived. This may
happen if a parent exits without having reaped the exit status of some or all of its children. In that case, those children are reparented
to PID 1. See init(1M), which periodically reaps such processes.
An irresponsible parent process may not exit for a very long time and thus leave zombies on the system. Since the operating system destroys
nearly all components of a process before it becomes defunct, such defunct processes do not normally impact system operation. However, they
do consume a small amount of system memory.
preap forces the parent of the process specified by pid to waitid(3C) for pid, if pid represents a defunct process.
preap will attempt to prevent the administrator from unwisely reaping a child process which might soon be reaped by the parent, if:
o The process is a child of init(1M).
o The parent process is stopped and might wait on the child when it is again allowed to run.
o The process has been defunct for less than one minute.
OPTIONS
The following option is supported:
-F Forces the parent to reap the child, overriding safety checks.
OPERANDS
The following operand is supported:
pid Process ID list.
EXIT STATUS
The following exit values are returned by preap, which prints the exit status of each target process reaped:
0 Successfully operation.
non-zero Failure, such as no such process, permission denied, or invalid option.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWesu (32-bit) |
+-----------------------------+-----------------------------+
| |SUNWesxu (64-bit) |
+-----------------------------+-----------------------------+
SEE ALSO proc(1), init(1M), waitid(2), wait(3C), waitpid(3C), proc(4), attributes(5)WARNINGS
preap should be applied sparingly and only in situations in which the administrator or developer has confirmed that defunct processes will
not be reaped by the parent process. Otherwise, applying preap may damage the parent process in unpredictable ways.
SunOS 5.10 26 Mar 2001 preap(1)