toshimaru

# Check server process is using jemalloc
# ref. [Japanese] https://tech.studyplus.co.jp/entry/2019/09/09/094140
class AppController < ActionController::Base
  def show
    r = `strings /proc/#{Process.pid}/maps | grep jemalloc`
    render plain: "<h1>#{ENV['LD_PRELOAD'].presence || 'empty'}</h1><pre>#{r}</pre>"
  end
end

lodi-g

Prepare server

• sudo hostnamectl set-hostname example.com
• sudo apt install mailutils postfix
• • Choose "internet site", and type your domain (example.com)

Test postfix

• mail [email protected] -s "Subject"
• You should receive a mail from [email protected]

basti

AWS S3 now uses JSON for CORS configuration and cors.json is minimal configuration for Rails 7 direct uploads.

ppoffice

1. Install Termux, an Android terminal emulator that provides a Linux execution environment and various tools.

2. Update system packages in Termux:

   $ pkg update -y

   

ragul28

• Scaling k8s daemonset down to zero

kubectl -n kube-system patch daemonset myDaemonset -p '{"spec": {"template": {"spec": {"nodeSelector": {"non-existing": "true"}}}}}'

• Scaling up k8s daemonset

kubectl -n kube-system patch daemonset myDaemonset --type json -p='[{"op": "remove", "path": "/spec/template/spec/nodeSelector/non-existing"}]'

mohanpedala

Table of Contents

• set -e, -u, -x, -o pipefail
• set -e
• set -x
• set -u
• set -o pipefail
• Setting IFS
• Original Reference

set -e, -u, -x, -o pipefail

giannisp

After automatically updating Postgres to 10.0 via Homebrew, the pg_ctl start command didn't work.
The error was "The data directory was initialized by PostgreSQL version 9.6, which is not compatible with this version 10.0."

Database files have to be updated before starting the server, here are the steps that had to be followed:

# need to have both 9.6.x and latest 10.0 installed, and keep 10.0 as default
brew unlink postgresql
brew install [email protected]
brew unlink [email protected]
brew link postgresql

chenkie

import { 
  HttpInterceptor, 
  HttpRequest, 
  HttpResponse, 
  HttpHandler, 
  HttpEvent 
} from '@angular/common/http';
import 'rxjs/add/operator/map';

@Injectable()

jdeathe

How to install/run Cron in a Docker Container

Example crontab entry for testing

• Append a timestamp to the log file every minute /var/log/cron.
• Append "tick" and "tock" in alternate minutes to /var/log/cron.

* * * * * /bin/date --rfc-3339=seconds >> /var/log/cron
*/2 * * * * /bin/echo 'tick' >> /var/log/cron

equivalent

#!/usr/bin/env ruby
require "openssl"
require 'digest/sha2'
require 'base64'

# We use the AES 256 bit cipher-block chaining symetric encryption
alg = "AES-256-CBC"

# We want a 256 bit key symetric key based on some passphrase
digest = Digest::SHA256.new