10 More Discussions You Might Find Interesting
1. IP Networking
Which one should I use in '/etc/hosts'?
Please explain in details.
Random quotes on the topic: (2 Replies)
Discussion started by: useretail
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2. Shell Programming and Scripting
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)
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3. Solaris
I was checking routing table, and noticed that our server has a lot packets from localhost:
Routing Table: IPv4
Destination Gateway Flags Ref Use Interface
-------------------- -------------------- ----- ----- ------ ---------
..
127.0.0.1 127.0.0.1 ... (1 Reply)
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4. Solaris
I have just installed Solaris 10 X86 today, but I can't use internet at all on it.
When I was installing it, it only asked me to create a hostname, without even asking me this computer is "networked" or "non-networked".
After I finished installation, I use "netstat -rn" command, and only see... (3 Replies)
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5. Shell Programming and Scripting
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)
Discussion started by: alex_5161
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6. UNIX for Dummies Questions & Answers
Hi All,
Can anyone please let me know the syntax / how to pick up the Return Code ( RC) from the mailx command and return it to SAS uisng 'system()' function and '${?}'.
I am in a process to send the mail automatically with an attachment to bulk users. I have used 'Mailx' and 'Unencode'... (0 Replies)
Discussion started by: manas6
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7. Shell Programming and Scripting
I have a script to download a file using wget.
It works if I execute it from the command line.
But, if I run it in cron, it doesnt work and I am getting the following in the cron log:
> CMD: /export/home/username/test
> username 23159 c Tue Aug 1 14:40:00 2006
< username 23159 c Tue Aug ... (1 Reply)
Discussion started by: BG_JrAdmin
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8. Shell Programming and Scripting
:cool:
I need to execute a shell script to do the following:
cat a file
run two back ground processes using the first two values from the file
wait till those background processes finish
run two more background processes using the next two values from the file
wait till those background... (1 Reply)
Discussion started by: halo98
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9. UNIX for Advanced & Expert Users
Hi Guys,
I was just wondering if anybody can help me with this problem.
OK, how we can get a value back from PL/SQL Script (not stored procedure/function)
See the below example: (for example aaa.sh)
#!/bin/ksh
VALUE=`sqlplus -s user/password@test_id <<EOF
@xxx.sq
EOF`
echo $VALUE
... (7 Replies)
Discussion started by: Shaz
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10. Shell Programming and Scripting
I have created a shell script that spawns multiple background processes (spawns sqlplus application). I use an array to capture the process id of those background processes. I then loop through the array and issue a 'wait' command to wait on the process id that was captured in the array. I am... (2 Replies)
Discussion started by: max_largo
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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)