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@bzerangue
bzerangue / json-to-ndjson.md
Last active January 31, 2024 20:57
JSON to NDJSON

NDJSON is a convenient format for storing or streaming structured data that may be processed one record at a time.

  • Each line is a valid JSON value
  • Line separator is ‘\n’

1. Convert JSON to NDJSON?

cat test.json | jq -c '.[]' > testNDJSON.json
#!/usr/bin/env bash -x
# Creates RAM disk.
#
# SYNOPSIS
# create_ramdisk [size [label]]
#
# OPTIONS
# size: RAM disk size in megabytes. Default: 1024
# label: RAM disk volume label. Default: UUID
FFmpeg has been removed from Ubuntu 14.04 and was replaced by Libav. This decision has been reversed so that FFmpeg is available now in Ubuntu 15.04 again, but there is still no official package for 14.04. In this tutorial, I will show you how to install FFmpeg from mc3man ppa. Add the mc3man ppa:
sudo add-apt-repository ppa:mc3man/trusty-media
And confirm the following message by pressing <enter>:
Also note that with apt-get a sudo apt-get dist-upgrade is needed for initial setup & with some package upgrades
More info: https://launchpad.net/~mc3man/+archive/ubuntu/trusty-media
Press [ENTER] to continue or ctrl-c to cancel adding it
Update the package list.
@vongosling
vongosling / gist:9929680
Last active January 31, 2024 04:49
Performance Tuning

Three system configuration parameters must be set to support a large number of open files and TCP connections with large bursts of messages. Changes can be made using the /etc/rc.d/rc.local or /etc/sysctl.conf script to preserve changes after reboot.

1. /proc/sys/fs/file-max: The maximum number of concurrently open files.

fs.file-max = 1000000

2. /proc/sys/net/ipv4/tcp_max_syn_backlog: Maximum number of remembered connection requests, which are still did not receive an acknowledgment from connecting client. The default value is 1024 for systems with more than 128Mb of memory, and 128 for low memory machines.

net.ipv4.tcp_max_syn_backlog = 3240000

3. /proc/sys/net/core/somaxconn: Limit of socket listen() backlog, known in userspace as SOMAXCONN. Defaults to 128.

net.core.somaxconn = 3240000

@stephenhardy
stephenhardy / git-clearHistory
Created April 26, 2013 22:14
Steps to clear out the history of a git/github repository
-- Remove the history from
rm -rf .git
-- recreate the repos from the current content only
git init
git add .
git commit -m "Initial commit"
-- push to the github remote repos ensuring you overwrite history
git remote add origin git@github.com:<YOUR ACCOUNT>/<YOUR REPOS>.git
@drizzt
drizzt / mac.c
Created March 16, 2011 15:07
Some useful C functions to manage mac addresses
/**
* @brief Some useful C functions to manage mac addresses
* @file
*/
#include <stdio.h>
#include <inttypes.h>
#include <limits.h>
/** Convert hex mac address to uint64_t