bash has the interesting exec command which allows you replace the current shell with the command, this sends a HUP to all processes running in the shell
ie
I'm trying to create a script that allows me to determine all the pid's that spawned from an original process(ie - who's running this command)....
I've created a script that searches the processes running based on an argument passed the script. It then is to get the parent pid and look that... (3 Replies)
Hello everyone , I am looking for a better solution then the one I have created for the my Task
The task is:
Create an automated script that will check for Uploads in a specified Directory and move them to another specified Directory if the files are completely uploaded.
Files are FTP'd to... (2 Replies)
################################################################
Copy this script to your path from where you want to search for all the files and directories in subdirectories recursively.
#################################################################
code starts here... (2 Replies)
Hello
i have a requirement where in a file i will get string. The length could be from 1 to 20. if the string is less than 6 characters ( ex: ABCD) . i need to append 'X' on right hand side to make it 6 characters (ex: ABCDXX). if suppose i get the same string from the file as ABCDXX then i... (5 Replies)
I have a batch of mkv video files I would like to transcode to a more compressed format. After spending a significant amount of time experimenting with various parameters I think I have found the handbrake settings that give the best compromise. I now want to construct a simple bash script... (4 Replies)
Hello. I am trying to create a script that recursively looks at my folder structure, and extracts any .7z files that have not already been extracted yet. I know that all .7z files only have a single .txt file in them, and the only .txt file in any directory would be from that .7z file.
I am... (3 Replies)
I have a shell script (.sh) and I want to pass a parameter value to the awk command but I am getting exception, please assist.
diff=$1$2.diff
id=$2 new=new_$diff
echo "My id is $1"
echo "I want to sync for user account $id"
##awk command I am using is as below
cat $diff | awk... (2 Replies)
Dear Unix gurus,
We have a config shell script file which has 30 variables which needs to be passed to master unix shell script that invokes oracle database sessions. So those 30 variables need to go through the database sessions (They are inputs) via a shell script. one of the variable name... (1 Reply)
Dear Unix gurus,
We have a config shell script file which has 30 variables which needs to be passed to master unix shell script that invokes oracle database sessions. So those 30 variables need to go through the database sessions (They are inputs) via a shell script. one of the variable name... (1 Reply)
Discussion started by: dba1981
1 Replies
LEARN ABOUT DEBIAN
system
SYSTEM(3) Linux Programmer's Manual SYSTEM(3)NAME
system - execute a shell command
SYNOPSIS
#include <stdlib.h>
int system(const char *command);
DESCRIPTION
system() executes a command specified in command by calling /bin/sh -c command, 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(2) 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 command 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
C89, C99, POSIX.1-2001.
NOTES
If the _XOPEN_SOURCE feature test macro is defined (before including any header files), then the macros described in wait(2) (WEXITSTA-
TUS(), etc.) are made available when including <stdlib.h>.
As mentioned, system() ignores SIGINT and SIGQUIT. This may make programs that call it from a loop uninterruptible, 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 set-user-ID or set-group-ID 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 set-user-ID or set-group-ID 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.)
In versions of glibc before 2.1.3, the check for the availability of /bin/sh was not actually performed if command was NULL; instead it was
always assumed to be available, and system() always returned 1 in this case. Since glibc 2.1.3, this check is performed because, even
though POSIX.1-2001 requires a conforming implementation to provide a shell, that shell may not be available or executable if the calling
program has previously called chroot(2) (which is not specified by POSIX.1-2001).
It is possible for the shell command to return 127, so that code is not a sure indication that the execve(2) call failed.
SEE ALSO sh(1), signal(2), wait(2), exec(3)COLOPHON
This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
2010-09-10 SYSTEM(3)