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# https://www.casler.org/wordpress/synology-ssd-cache-on-external-devices/
echo "Current values"
more /etc.defaults/synoinfo.conf | grep maxdisk
more /etc.defaults/synoinfo.conf | grep usbportcfg
more /etc.defaults/synoinfo.conf | grep esataportcfg
more /etc.defaults/synoinfo.conf | grep internalportcfg
sudo sed -i.bak -e 's/maxdisks=\".*$/maxdisks=\"24\"/g' -e 's/usbportcfg=\".*$/usbportcfg=\"0x00\"/g' -e 's/esataportcfg=\".*$/esataportcfg=\"0x00\"/g' -e 's/internalportcfg=\".*$/internalportcfg=\"0xffffff\"/g' /etc.defaults/synoinfo.conf
echo "Updated values"
more /etc.defaults/synoinfo.conf | grep maxdisk
more /etc.defaults/synoinfo.conf | grep usbportcfg

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# https://stackoverflow.com/a/38731052

# variable substitution, leading tab retained, overwrite file, echo to stdout

tee /path/to/file <<EOF
${variable}
EOF


# no variable substitution, leading tab retained, overwrite file, echo to stdout

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#!/bin/bash
# This script is designed to work only with recent bash implementations, not ash/dash etc.

# @file      show-cron-jobs.sh
#
#             published at:
#               https://gist.github.com/myshkin-uk/d667116d3e2d689f23f18f6cd3c71107
#
#             @NOTE DGC 2-Sep-2019
#                      There is one comment there that the script doesn't run as expected.

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# count number of active task inside of all user crontab
# sample with excluding a string containing "str"

for c in $(sudo ls  /var/spool/cron); do sudo crontab -u $c -l 2>/dev/null | grep -v -e '^$' | grep -v -e '^#' | grep  -v "crontab;" | grep -v "str"; done | wc -l

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# launch a shell with an empty env 
# https://unix.stackexchange.com/a/291913

 env -i bash --noprofile --norc
 
# source var file and show a specific var
 env -i bash --noprofile --norc -c ". somefile.sh; echo $VAR;"

# backup/restore env
# https://unix.stackexchange.com/questions/284382/export-save-and-import-source-shell-variables

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traefik:
    image: traefik:v2.1.6
    container_name: traefik
    volumes:
      - "traefik.enable=true"
      - /var/run/docker.sock:/var/run/docker.sock:ro
      - ./traefik-conf.yml:/etc/traefik/traefik.yml
      - ./traefik-services.yml:/etc/traefik/services.yml
    labels:
      - "traefik.http.routers.blog.entrypoints=web_main"

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# Solutions from https://stackoverflow.com/a/20855353




# SOLUTION 1 : analyse at the current level of execution (do not step into code)

# get https://www.f-hauri.ch/vrac/cours_truc-et-astuces_2012-04-03/add/elap.bash-v2

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1. SSH key based authentification

1.1. Summary

• Autorize SSH connection from a local machine to a distant SSH machine without using a password
• Configure VSCode to use this SSH configuration
• DOC : https://code.visualstudio.com/docs/remote/troubleshooting
• NOTE : how to install OpenSSH Server on windows : https://learn.microsoft.com/fr-fr/windows-server/administration/openssh/openssh_install_firstuse?tabs=gui

1.2. Table of contents

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To invoke JupyterLab with Spark capabilities there are two ways. An ad hoc method is to just state on the command line that JupyterLab should use pyspark as kernel. For instance starting JupyterLab with Python 3.6 (needs to be consistent with your Spark distribution), 20 executors each having 5 cores might look like this:

PYSPARK_PYTHON=python3.6 PYSPARK_DRIVER_PYTHON="jupyter" PYSPARK_DRIVER_PYTHON_OPTS="notebook --no-browser --port=8899" /usr/bin/pyspark2 --master yarn --deploy-mode client --num-executors 20 --executor-memory 10g --executor-cores 5 --conf spark.dynamicAllocation.enabled=false

In order to be able to create notebooks with a specific PySpark kernel directly from JupyterLab, just create a file ~/.local/share/jupyter/kernels/pyspark/kernel.json holding:

{
 "display_name": "PySpark",
 "language": "python",

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#https://stackoverflow.com/a/10965292

[ -n "$var" ] && echo "var is set and not empty"
[ -z "$var" ] && echo "var is unset or empty"
[ "${var+x}" = "x" ] && echo "var is set"  # may or may not be empty
[ -n "${var+x}" ] && echo "var is set"  # may or may not be empty
[ -z "${var+x}" ] && echo "var is unset"
[ -z "${var-x}" ] && echo "var is set and empty"