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@nickjacob
nickjacob / systemd-prblm.service
Last active March 17, 2023 16:11
execute arbitrary bash code/variable substitution in systemd units
[Unit]
Description=Demonstrate Bash
[Service]
ExecStartPre=/usr/bin/bash -c "/usr/bin/systemctl set-environment MYVAR=$(( 2 + 2 ))"
ExecStart=/usr/bin/echo "2 + 2 = ${MYVAR}"
@elithrar
elithrar / wale_postgres_recovery.md
Last active May 3, 2021 15:38
WAL-E + Postgres 9.x (single server + DB) Setup and Recovery

A quick "how to" on what you need to do to both setup AND recover a single-server PostgreSQL database using WAL-E

  • WAL-E: https://github.com/wal-e/wal-e
  • Assuming Ubuntu 12.04 LTS ("Precise")
  • We'll be using S3. Make sure you have an IAM in a group with GetObject, ListBucket and PutObject on the bucket you want to use (and that it's not public).

Setup:

  1. These packages:
@lelandbatey
lelandbatey / whiteboardCleaner.md
Last active April 25, 2024 02:01
Whiteboard Picture Cleaner - Shell one-liner/script to clean up and beautify photos of whiteboards!

Description

This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.

The script is here:

#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"

Results

@simianhacker
simianhacker / json_path.sql
Last active May 13, 2019 17:40
Here is a set of functions for working with a PostgreSQL+JSON+PLV8 database.
-- Function: json_path(json, text)
-- DROP FUNCTION json_path(json, text);
CREATE OR REPLACE FUNCTION json_path(data json, path text)
RETURNS text AS
$BODY$
/* JSONPath 0.8.0 - XPath for JSON
*
* Copyright (c) 2007 Stefan Goessner (goessner.net)
@MohamedAlaa
MohamedAlaa / tmux-cheatsheet.markdown
Last active May 7, 2024 06:03
tmux shortcuts & cheatsheet

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname
@hellerbarde
hellerbarde / latency.markdown
Created May 31, 2012 13:16 — forked from jboner/latency.txt
Latency numbers every programmer should know

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

@danielestevez
danielestevez / gist:2044589
Last active April 10, 2024 07:51
GIT Commit to an existing Tag
1) Create a branch with the tag
git branch {tagname}-branch {tagname}
git checkout {tagname}-branch
2) Include the fix manually if it's just a change ....
git add .
git ci -m "Fix included"
or cherry-pick the commit, whatever is easier
git cherry-pick {num_commit}