I'm sure I'm doing something wrong but as I am new to bash shell scripting I'm not sure what:
Here's the code
webalizer.conf is sitting in the same directory as this file which is named webalizer.sh. Can someone tell me if I've got the syntax right -- it that's correct? I'm executing the... (3 Replies)
Hi guys, I'm new to the forum so forgive me if I'm sounding ... daft.
I currently work in a Tech Support role. Every day we have to generate data by running around 10 .sh scripts. I was thinking instead of having to ./filename 10 times is it possible to right a new script that will run these for... (16 Replies)
I am writing a shell script in bash one of the thing I want to show is size of export /home
du -sk /export/home/oracle | cut -c 1-5
echo "kbytes"
when I run the script kbytes shows up in the second line, How can I append kbytes on the same line, such as
61233 kbytes
please guide
thanks (2 Replies)
I have a bash script, but it needs to have a simple protection with password.
So if a user wants to run the script , there should be a kdialog to asks for a password.If the password is correct the script starts to run.
It should not be the passord of root or another admin user.Just a password in... (2 Replies)
to gather the cpu utilization from a system in 5 minute intervals and direct output to file.
I'm new at scripting and while this seems like an easy task I'm confused on where to start. thanks for any help (1 Reply)
Hi to everyone here,
I'm a new user and relatively-new linuxer.
I'm trying to write a script that checks if every file from a directory is present in a given list and if not, delete it.
should be simple. But I think I've done half the work only:
this is to create the reference list:
for c... (2 Replies)
This is the command. Assume file1 exists but file2 does not:
ls file1 file2 >newfile 2>&1
This simply makes a text file with two lines: file1 \n file2 could not be found. What I don't understand is that when you run this command: ls file1 file2 >newfile, it prints "file2 could not be found" to... (1 Reply)
I have a text file called file1 which contains the text: "ls -l"
When I enter this command:
bash < file1 > file1
file1 gets erased. However if I enter this command:
bash < file1 > newfile
the output from "ls -l" is stored in newfile. My question is why doesn't file1's text ("ls -l") get... (3 Replies)
Hello all!
This is my first post and I'm very new to programming. I would like help creating a simple perl or bash script that I will be using in my work as a junior bioinformatician.
Essentially, I would like to take a tab-delimted or .csv text with 3 columns and write them to a "3D" matrix:
... (16 Replies)
Well I searched the net with varying success, but it seems kinda hard to find a one/max 2 lined command to:
strip all *.png files in the folder from their first two characters.
Any help is appreciated.
In DOS commandline of course... (17 Replies)
Discussion started by: pasc
17 Replies
LEARN ABOUT CENTOS
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 3.53 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)