06-07-2007
When you use the system() or the backticks in perl, the program will do a fork and exec. This will result in two processes. Why is there a restriction on the number of processes that you can create?
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hi:
I am currently working on a program which requires direct its ouput to a file here is an example
./proram arg_1 arg_2
when program ends all output will be arg_2 file
Is that possible I am not a bad programmer, However I am stuck there.
Can anyone give a hint?
Thanks
SW (1 Reply)
Discussion started by: slackware
1 Replies
2. UNIX for Dummies Questions & Answers
Ahhhrrrggg I'm having a brain fart...
I want to take the output of a command and redirect it to a file...
This works....
$ man cp | cat >> copy_help
but this doesn't
keytool -help |cat >> keytool_help
It just produces... these lines...
more keytool_help
] ...
... (11 Replies)
Discussion started by: jimmyc
11 Replies
3. UNIX for Dummies Questions & Answers
Hi all!!
is possible to assign the output of some command to filename, i.e.
grep_output.txt
Otherwise, I want to open a new file which name is inside another, how can I do it?
Thanks a lot! (7 Replies)
Discussion started by: csecnarf
7 Replies
4. Shell Programming and Scripting
Hi guys,
i have a script named purgeErrors.ksh, when i execute this script i need to redirect the output to a log file in the same directory, how can i do that ??
-- Aditya (5 Replies)
Discussion started by: chaditya
5 Replies
5. Shell Programming and Scripting
Hi All,
I want to redirect only the file names to a new file from the ls -ltr directroy. how Can i do it.
my ls -ltr output will be as below.
-rwxr-xr-x 1 118 103 28295 Jul 26 2006 event.podl
-rwxr-xr-x 1 118 103 28295 Jul 26 2006 xyz.podl
I want my new file... (6 Replies)
Discussion started by: girish.raos
6 Replies
6. Shell Programming and Scripting
Below script perfectly works, giving below mail output. BUT, I want to make the script mail only if there are any D-Defined/T-Transition/B-Broken State WPARs and also to copy the output generated during monitoring to a temporary log file, which gets cleaned up every week. Need suggestions.
... (4 Replies)
Discussion started by: aix_admin_007
4 Replies
7. UNIX for Dummies Questions & Answers
Hi ,
I am trying to redirect output of echo to a file.So i wrote a function named printline.Here is my sample script
myscript.sh
function printline()
{
echo "$1" >> myfile.log
}
usage()
{
printLine "********************USAGE*************************"
printLine "Script takes... (12 Replies)
Discussion started by: ASC
12 Replies
8. Shell Programming and Scripting
Hi Guys,
I want to redirect the output of 3 scripts to a file and then mail the output of those three scripts.
I used below but it is not working:
OFILE=/home/home1/report1
echo "report1 details" > $OFILE
=/home/home1/1.sh > $OFILE
echo... (7 Replies)
Discussion started by: Vivekit82
7 Replies
9. UNIX for Dummies Questions & Answers
I have the below script, but when i execute it is still printing to screen is there a way i can stop this and just print everything to the log file. Thank you.
#!/bin/bash
exec > >(tee "/var/log/ScriptLogs/called_from_incrontab.log") 2>&1
DIR="$1"
FILE="$2"
echo "STEP 1: Datafile... (5 Replies)
Discussion started by: Ariean
5 Replies
10. Shell Programming and Scripting
Hi,
I am using cygwin.
Below is my script that reads all ip ports for iplist.txt and telnets to it.
(
file="iplist.txt"
while read line
do
echo $line
echo $(telnet $line)
done <"$file"
) > output2.txt
~
while the output2.txt gets the first echo but does not show the second... (2 Replies)
Discussion started by: mohtashims
2 Replies
FORK(2) BSD System Calls Manual FORK(2)
NAME
fork -- create a new process
SYNOPSIS
#include <unistd.h>
pid_t
fork(void);
DESCRIPTION
fork() causes creation of a new process. The new process (child process) is an exact copy of the calling process (parent process) except for
the following:
o The child process has a unique process ID.
o The child process has a different parent process ID (i.e., the process ID of the parent process).
o The child process has its own copy of the parent's descriptors. These descriptors reference the same underlying objects, so that,
for instance, file pointers in file objects are shared between the child and the parent, so that an lseek(2) on a descriptor in the
child process can affect a subsequent read or write by the parent. This descriptor copying is also used by the shell to establish
standard input and output for newly created processes as well as to set up pipes.
o The child processes resource utilizations are set to 0; see setrlimit(2).
RETURN VALUES
Upon successful completion, fork() returns a value of 0 to the child process and returns the process ID of the child process to the parent
process. Otherwise, a value of -1 is returned to the parent process, no child process is created, and the global variable errno is set to
indicate the error.
ERRORS
fork() will fail and no child process will be created if:
[EAGAIN] The system-imposed limit on the total number of processes under execution would be exceeded. This limit is configuration-
dependent.
[EAGAIN] The system-imposed limit MAXUPRC (<sys/param.h>) on the total number of processes under execution by a single user would
be exceeded.
[ENOMEM] There is insufficient swap space for the new process.
LEGACY SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
The include file <sys/types.h> is necessary.
SEE ALSO
execve(2), sigaction(2), wait(2), compat(5)
HISTORY
A fork() function call appeared in Version 6 AT&T UNIX.
CAVEATS
There are limits to what you can do in the child process. To be totally safe you should restrict yourself to only executing async-signal
safe operations until such time as one of the exec functions is called. All APIs, including global data symbols, in any framework or library
should be assumed to be unsafe after a fork() unless explicitly documented to be safe or async-signal safe. If you need to use these frame-
works in the child process, you must exec. In this situation it is reasonable to exec yourself.
4th Berkeley Distribution June 4, 1993 4th Berkeley Distribution