I have a program that is projected to use a few GB of lmdb diskspace (it’s a blockchain, and we’re moving away from leveldb due to its lack of ACID, which I need for some future plans). Is it possible to run that program with that database on a Raspberry Pi without adding more swap (with >1 GB …
Linux Installation libX11-devel
I am trying to build QT4 (porting from Redhat 5 to 7 with an upgraded gcc compiler) in RedHat 7 and I was getting an error saying X11/Xlib.h can’t be found. Anyways, after doing some research most people said to install libX11-devel to get those x11 libraries. Since I am using an offline machine I can&#…
Set env variable in sudo when provisioning Vagrant
I’m trying to install a python package in a Vagrant box that runs in Ubuntu 14 with sudo, this package requires to set an env variable before. I have tried the following commands, but it did not recognize the env variable when provisioning Vagrant: sudo AIRFLOW_GPL_UNIDECODE=yes sudo pip install apache-…
Clone a folder / raid on a folder?
I have two hard drive of 4Tb connected to my raspberry pi. Let’s call them A and B. I have some folders on A that have to be copied on B. At all the time, something like a RAID10 on some folder. So, if I copy test.jpg in disk A, test.jpg has to be copied on disk B. If I
How to ping in linux until host is known with X seconds timeout?
Im trying to wait for a device to boot up in my code and i dont want to use sleep to wait for him. my problem is that sometimes the device fail to boot and im stuck in a loop when using: How can i try to ping to the device for X seconds and print “DEAD” or “ALIVE” using
Stop bash script from dying when exiting Java / Kotlin application
I’m starting a bash script from Kotlin, but the bash script stops running as soon as the Kotlin application exits. Where script is a liquidsoap script and input is a parameter that’s being passed into the script Typically, it’ll run something like the following: liq then executes a liquidsoa…
Who creates the Threads? Programmer, OS, Compiler OR Programming Language?
who is the first and main creator of threads? if a programming language does not support threads, can we run multithreading on it? if an OS does not support threads, can we run multithreading on it? Answer Lets look at definations: Kernel-Level and User-Level threads; cs.iit.edu User-Level Threads Kernel-Leve…
How do I create a file I can stream data to in Python?
I’d like to create a file similar to those under /dev that I can stream lines of text to without actually writing anything to the disk. I want to still be able to read this stream like a regular text file. Answer Call the os.mkfifo function, then open the file it creates as normal. Anything that gets wr…
tar package has different checksum for exactly the same content
Packaging a folder on a SUSE Linux Enterprise Server 12 SP3 system using GNU tar 1.30 always gives different md5 checksums although the file contents do not change. I run tar to package my folder that contains a simple text file: Nevertheless, although the content is exactly the same, the resulting tar always…
Understanding read syscall
I’m reading man read manual page and discovered that it was possible to read less then the desired number of bytes passed in as a parameter: It is not an error if this number is smaller than the number of bytes requested; this may happen for example because fewer bytes are actually available right now (…