I can supply a translation from head to dd, but I need to understand why you used the above command line on Linux rather than just:
and I need to understand what -c 6000k means to you. The Linux head man page defines the meaning for 6000kB and for 6000K, but it does not specify any meaning for 6000k???
it means nothing to me. please show me your suggested solution.
:mad: I did this the other day but one of my support personnel removed my history so i could call it back up to remeber the exact command since i am air-headed at times. I am trying to take a 30 MEG file off the system and drop it to tape then i want to make the file go back to being 0 bytes so... (1 Reply)
I'm doing a bit of hex editing with dd and I can replace values fairly simply. However, I've run across a situation where I need to delete bytes in the file and I'm not sure how to do that. For example:
Input file has:
1234567890
Output needs to be:
123abc90
I tried this:
printf... (6 Replies)
Hi all,
Does anybody know or guide me on how to remove the first N bytes and the last N bytes from a binary file? Is there any AWK or SED or any command that I can use to achieve this?
Your help is greatly appreciated!!
Best Regards,
Naveen. (1 Reply)
What is the easiest way to inspect the bytes stored in a file?
Ideally, If my file was 10 bytes each of which had only the high bit set, I'd be able to browse for it and get output like this:
01 - 10000000
02 - 10000000
03 - 10000000
04 - 10000000
05 - 10000000
06 - 10000000
07 -... (7 Replies)
Hi Guyz,
I need to capture first N Bytes from the first line of my file.
Eg. If i have following data in File1
414d51204541495052475731202020204a910846230e420c Hello 3621363663212 Help Required
Then, i want the value of first 48 Bytes to be stored in a variable.
That is, variable... (5 Replies)
While running script I am getting an error like
Few lines in data are not being processed.
After googling it I came to know that adding such line would give some memory to it
ini_set("memory_limit","64M");
my input file size is 1 GB.
Is that memory limit is based on RAM we have on... (1 Reply)
Hi,
If I want to copy a 1024 byte data stream in to the target location in 3-bytes chunk, I guess I can use the following script.
dd bs=1024 count=3 if=/src of=/dest
But, I would like to know, how to do it via a C program. I have tried this with memcpy(), that did not help. (3 Replies)
Hello guys. I really hope someone will help me with this one..
So, I have to write this script who:
- creates a file home/student/vmdisk of 10 mb
- formats that file to ext3
- mounts that partition to /mnt/partition
- creates a file /mnt/partition/data. In this file, there will... (1 Reply)
hello,
suppose, entered input is of 1-40 bytes, i need it to be converted to 40 bytes exactly.
example: if i have entered my name anywhere between 1-40 i want it to be stored with 40 bytes exactly.
enter your name:
donald duck (this is of 11 bytes)
expected is as below - display 11... (3 Replies)
Discussion started by: shravan.300
3 Replies
LEARN ABOUT PHP
get_robust_list
GET_ROBUST_LIST(2) Linux System Calls GET_ROBUST_LIST(2)NAME
get_robust_list, set_robust_list - get/set list of robust futexes
SYNOPSIS
#include <linux/futex.h>
#include <sys/types.h>
#include <syscall.h>
long get_robust_list(int pid, struct robust_list_head **head_ptr,
size_t *len_ptr);
long set_robust_list(struct robust_list_head *head, size_t len);
Note: There are no glibc wrappers for these system calls; see NOTES.
DESCRIPTION
These system calls deal with per-thread robust futex lists. These lists are managed in user space: the kernel knows only about the loca-
tion of the head of the list. A thread can inform the kernel of the location of its robust futex list using set_robust_list(). The
address of a thread's robust futex list can be obtained using get_robust_list().
The purpose of the robust futex list is to ensure that if a thread accidentally fails to unlock a futex before terminating or calling
execve(2), another thread that is waiting on that futex is notified that the former owner of the futex has died. This notification con-
sists of two pieces: the FUTEX_OWNER_DIED bit is set in the futex word, and the kernel performs a futex(2) FUTEX_WAKE operation on one of
the threads waiting on the futex.
The get_robust_list() system call returns the head of the robust futex list of the thread whose thread ID is specified in pid. If pid is
0, the head of the list for the calling thread is returned. The list head is stored in the location pointed to by head_ptr. The size of
the object pointed to by **head_ptr is stored in len_ptr.
Permission to employ get_robust_list() is governed by a ptrace access mode PTRACE_MODE_READ_REALCREDS check; see ptrace(2).
The set_robust_list() system call requests the kernel to record the head of the list of robust futexes owned by the calling thread. The
head argument is the list head to record. The len argument should be sizeof(*head).
RETURN VALUE
The set_robust_list() and get_robust_list() system calls return zero when the operation is successful, an error code otherwise.
ERRORS
The set_robust_list() system call can fail with the following error:
EINVAL len does not equal sizeof(struct robust_list_head).
The get_robust_list() system call can fail with the following errors:
EPERM The calling process does not have permission to see the robust futex list of the thread with the thread ID pid, and does not have
the CAP_SYS_PTRACE capability.
ESRCH No thread with the thread ID pid could be found.
EFAULT The head of the robust futex list can't be stored at the location head.
VERSIONS
These system calls were added in Linux 2.6.17.
NOTES
These system calls are not needed by normal applications. No support for them is provided in glibc. In the unlikely event that you want
to call them directly, use syscall(2).
A thread can have only one robust futex list; therefore applications that wish to use this functionality should use the robust mutexes pro-
vided by glibc.
In the initial implementation, a thread waiting on a futex was notified that the owner had died only if the owner terminated. Starting
with Linux 2.6.28, notification was extended to include the case where the owner performs an execve(2).
The thread IDs mentioned in the main text are kernel thread IDs of the kind returned by clone(2) and gettid(2).
SEE ALSO futex(2), pthread_mutexattr_setrobust(3)
Documentation/robust-futexes.txt and Documentation/robust-futex-ABI.txt in the Linux kernel source tree
COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
Linux 2017-09-15 GET_ROBUST_LIST(2)