When I use mysqld_safe to start my MySQL in CentOS7: It get stuck in the mysqld_safe Starting mysqld daemon. I find the SO, do not find this post, and some similar, but is not stuck, they report error directly. MySQL version is 5.7.19 My requirement is change the user root’s password. Answer At last, I …
Can I use 1G superpages to back shared mmaps?
So far when I’ve tried using a file in /mnt/hugepages1G/ as the backing I get segfaults. It works fine if I use 2M superpages in /mnt/hugepages/ I think I read somewhere that I now can’t find that Linux only supports 2M pages for Shared memory? But I can’t swear to it. Can’t find it in…
get all aliases in linux shell
How to list all aliases defined in a shell. Like the command below to list all files/folders in a directory I have defined some alias in ~/.bashrc i want to list all that command Answer Are you wondering if you have a UNIX alias already set for a specific command? You can find it easily by issuing this on the
Changing nice value of a process has no effect in Linux
I read about APUE 3rd, 8.16 Process Scheduling, there is an example written to verify that changing nice value of a process will affect its priority, I rewrite the code like below: And the result of the example is shown below: NZERO = 20 parent nice:20 child nice:20, adjusted by 0 child now nice:20 parent cou…
Kernel debugging – gdb step jumps out of function
I’m trying to do understand the kernel network stack for a security research for my university. That’s why I try to debug the linux kernel. So far I’m doing quite well but I ran in a problem when trying to use qemu and gdb for debugging. The problem is as follows: I boot my linux system: mak…
“[Errno 13] Access denied” when connecting to USB
So I have been following these documentations so that I can print on my thermal printer through python. I am running Ubuntu and have the pyusb module installed. The printer is a Rongta RP58, and it’s idVendor and idProduct were found through the lsusb command (0fe6:811e). Just like in the instructions, …
How to view execution plans in SQL Server on Linux
I have SQL Server installed on Linux. It was installed from Microsoft’s repos as described here: https://learn.microsoft.com/en-us/sql/linux/quickstart-install-connect-ubuntu In MySql I used to write EXPLAIN in front of my query to see the execution plan. In SQL Server it doesn’t seem to work. But…
Ubuntu-16.04 + PHP-7.0.22 + ODBC not working
I have been trying to connect MSSQL from my ubantu 16.04 and i had use below tutorial: https://askubuntu.com/questions/578934/mssql-connection-from-ubuntu There is one problem while i am running below command from terminal is: It display below errors: I have follow instruction given by below link answer as we…
Ambari cluster + Service Auto Start Configuration by API
Ambari services can be configured to start automatically on system boot. Each service can be configured to start all components, masters and workers, or selectively. so how to enable all services in ambari cluster to start automatically on system boot by API ? Remark – by default all services are disabl…
linux spring tool suite (eclipse) launches from terminal but not from desktop
I am setting up Spring Tool Suite IDE on a linux mint cinnamon machine. I have installed the JDK, added it to my path. When I do java -version everything works. When I navigate to the folder containing Spring tool suite and execute it using ./STS it launches correctly. When I navigate to that file in finder, …