Thanks fmurphy for pointing out that important caveat. It could be easily adapted to use parted, but I do not have it installed on my current system. I have used it in a similar script in the past to find the offset for mounting HFS partitions in a GPT.
Quote:
Originally Posted by Corona688
I'm not sure these structures:
...do what you think they do. I'm not even sure what they're supposed to do. If you're trying to check if the string's blank, that would be -z
The string is treated as an expression and so returns false if empty and true otherwise. I am not sure if there is any benefit of the -z and -n tests over this form, but I have always used this way as I find it more readable as it corresponds with other languages.
Quote:
Originally Posted by Corona688
Also, a plain Bourne shell will never work with this code. Use #!/bin/bash or #!/bin/ksh to show which you designed it with
You have got me curious as it works for me and I thought I had a proper version of sh. I am used to having to use different code for sh and bash scripts, but like to use sh where possible.
Going to check the version I discovered my sh is an alias to dash. I have no idea what the differences are between the two, but annoyingly it seems I have been writing for that (and systems where sh points to bash) all along. So on anything else it is best to change the shebang to bash.
Hi,
I was wondering if any of you guys know of way to make applications that use sound device on linux to access it in a "non-exclusive manner", the aim is to be able to use more than one application that requires the sound device.
Thanks (0 Replies)
Hi,
we have running 8 box sles 9 cluster and on an nfs filesystem we have the problem which is grepped from /var/log/messages.
Jun 8 13:40:46 qnclpx02 kernel: attempt to access beyond end of device
Jun 8 13:40:46 qnclpx02 kernel: sdat: rw=0, want=8894615912, limit=314572800
Is there... (1 Reply)
Hello everyone,
I write a program (Linux & Solaris) that will run as non-root user, but the program must have rw access to a device /dev/ipmi (on linux) or /dev/bmc (on solaris).
What is the standard way of granting such access?
Linux:
chmod on /dev/ipmi ?
suid root my program?
Solaris:... (1 Reply)
Problem statement.
In this part of the assignment, delegates will create a pseudo-device and write a device driver for it. The pseudo-device provides a “backdoor” for gaining root access for a particular user. Instead of compiling the device driver into the kernel, delegate will create a module.... (1 Reply)
hi, i am on a quest to access and even mount if possible a drive on os x. there is no driver for the device, but it lists fine in the system profiler. can i access its location from the terminal? how? here is what i get on the system profiler:
Speed: Up to 480 Mb/sec
Manufacturer: SAMSUNG
... (3 Replies)
I am trying to load into the kernel a system-call dynamically (without restarting the kernel and compailing it) in an attempt to (once in kernel mode) write to user process's memory.
(I know there is a way to do this with the ptrace interface but it is not an option.)
I know the only way to... (1 Reply)
Equipment: DJI Phantom 3
I have the root and passwords access, but I cannot find out how to access the equipment.
There is a USB port going to a miniUSB that connects to the equipment, but on Windows is detecting the connection as being a Serial Port (COM3).
I need some help in order to gain... (5 Replies)
I cannot access or boot from my C drive. I'm running Zorin 9 and the drive is a Samsung SSD. The disk was encrypted on install, and that has not given me any problems before.
When I start the system it gets to the memory test page, and does not then load the password prompt, which it used to.... (1 Reply)
How to provide a client exclusive access to the NTP device or NTP server.
Example:
1. Configured md5 authentication for a subnet added below restriction line to the subnet as below in ntp.conf file. Also configured the keys and md5 authentication working .
restrict 192.168.1.0 mask... (1 Reply)
Hi,
Unable to make tape backup, please help.
/opt/ignite/bin/make_tape_recovery -a /dev/rmt/?mn -I -v -m tar -x inc_entire=vg00
* Creating local directories for configuration files and archive.
======= 04/25/16 16:28:08 IST Started /opt/ignite/bin/make_tape_recovery.
(Mon... (4 Replies)
Discussion started by: anuragr
4 Replies
LEARN ABOUT SUSE
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, then the macros described in wait(2) (WEXITSTATUS(), 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 3.25 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/.
2004-12-20 SYSTEM(3)