11-05-2002
Shell prog
I feel it is better to run child shell, so that once the child shell terminates, we can get the status of the shell which, in turn, returns the status of the command,....
Please repost if youneed any suggestions or research in UNIX, C,C++ and networking or kernel prog or embedded or system level....
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hello,
I still have problems when trying to figure out if the status of an ftp was successful. I ftp to different types (nt, vax, unix, etc...) of machines. I am trying to write a universal script that will ftp a file and then check to see if the ftp was successful. I have tried the... (12 Replies)
Discussion started by: blt123
12 Replies
2. Shell Programming and Scripting
hi, I set the crontab to execute script A every 5 minutes from 9:00 am to 4:00 pm everyday, now at 12:00am I want to run another script if and only if all the previous runs of script A return OK, can anyone tell me how it could be done? thank you very very much! (4 Replies)
Discussion started by: mpang_
4 Replies
3. Shell Programming and Scripting
Hi all
below is a snippet of my perl codesystem ("scp -pq $dest_file $path");How i can i trap the return status? ie if the scp fails how can i know ? (2 Replies)
Discussion started by: new2ss
2 Replies
4. HP-UX
I have the question:
How return the exit code from then assign :
VAR=$(command ) for ex. VAR=$(ls ....)
VAREXIT=$?
echo $VAREXIT
VAREXIT is equal to 0 if the directory exist or not exist. WHI??
if i execute the command direct from line-command , the value of $? is different if... (1 Reply)
Discussion started by: ZINGARO
1 Replies
5. Shell Programming and Scripting
Hi all
I'm trying to evalute the return status of a function without much success. I've put a very basic example below to explain.
check_ok() works fine but when used within an if statement, it always returns true, whether it is true or false. I'm guessing it returns true as the function... (4 Replies)
Discussion started by: tig2810
4 Replies
6. Shell Programming and Scripting
Hello,
I have a C++ binary that runs in my perl script. But, Currently, the binary is doing a core dump and i want to capture the retrun status of the binary to report as an issue.
Can you please help me on this.
Thanks,
Sateesh (1 Reply)
Discussion started by: kotasateesh
1 Replies
7. Shell Programming and Scripting
Hello,
I have a C++ binary that runs in my perl script. But, Currently, the binary is doing a core dump and i want to capture the retrun status of the binary to report as an issue.
Can you please help me on this.
Thanks,
Sateesh (1 Reply)
Discussion started by: kotasateesh
1 Replies
8. Shell Programming and Scripting
i have to run set of commands
command1
command2
command3
command4
Now Whenever any of these command fails i should quit while capturing error message.
Is there a better way then checking for $? after each command. (1 Reply)
Discussion started by: vickylife
1 Replies
9. UNIX for Dummies Questions & Answers
there is something wrong with my system. when I do this:
diff file1 file1 && echo 1
the output is 1.
but
diff file1 file2 >/dev/null && echo 1
output nothing
while
diff file1 file2 >/dev/null || echo 1
shows 1.
the same with "grep" return status. they are both GNU utilities.... (5 Replies)
Discussion started by: phil518
5 Replies
10. Shell Programming and Scripting
Hi can you explain me, what does variables $@ and $* return and how are they used, if can give me a sample example it could be helpful.
Thanks in advance,
Regards,
Abhishek S. (1 Reply)
Discussion started by: abhisheksunkari
1 Replies
system(3C) system(3C)
NAME
system - issue a shell command
SYNOPSIS
#include <stdlib.h>
int system(const char *string);
The system() function causes string to be given to the shell as input, as if string had been typed as a command at a terminal. The invoker
waits until the shell has completed, then returns the exit status of the shell in the format specified by waitpid(3C).
If string is a null pointer, system() checks if the shell exists and is executable. If the shell is available, system() returns a non-zero
value; otherwise, it returns 0. The standard to which the caller conforms determines which shell is used. See standards(5).
The system() function executes vfork(2) to create a child process that in turn invokes one of the exec family of functions (see exec(2)) on
the shell to execute string. If vfork() or the exec function fails, system() returns -1 and sets errno to indicate the error.
The system() function fails if:
EAGAIN The system-imposed limit on the total number of processes under execution by a single user would be exceeded.
EINTR The system() function was interrupted by a signal.
ENOMEM The new process requires more memory than is available.
USAGE
The system() function manipulates the signal handlers for SIGINT, SIGQUIT, and SIGCHLD. It is therefore not safe to call system() in a mul-
tithreaded process, since some other thread that manipulates these signal handlers and a thread that concurrently calls system() can inter-
fere with each other in a destructive manner. If, however, no such other thread is active, system() can safely be called concurrently from
multiple threads. See popen(3C) for an alternative to system() that is thread-safe.
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |Unsafe |
+-----------------------------+-----------------------------+
ksh(1), sh(1), exec(2), vfork(2), popen(3C), waitpid(3C), attributes(5), standards(5)
18 Dec 2003 system(3C)