Peter Mescalchin magnetikonline

Extract all files at every commit of a Git repository

Bash script to iterate all commits of a given Git repository and extract all files within each commit.

Example

With a Git repository at /path/to/repository and an empty directory at /path/to/output we can run:

./export.sh /path/to/repository /path/to/output

AWS CloudFormation YAML template - appending to list parameter types

Documenting this here, as I often forget (what I have found) is the best way to do this at the moment.

For example, you have a list of two existing security groups given to a stack and wish to create (and use) a third - attaching all to an ALB:

AWSTemplateFormatVersion: '2010-09-09'
Description: Example template

Bash getopt long options with values usage example

#!/bin/bash -e

ARGUMENT_LIST=(
  "arg-one"
  "arg-two"
  "arg-three"
)

MySQL user management cheatsheet

List all users
List connected users
Create user
- With mysql_native_password identity
- With auth_socket identity
Grant user specific permissions to database
Grant root-like permissions
List grants for user

Bash array usage cheatsheet

Creation
Get elements
Append element
Array length
Iteration
Pass array to function
Reference

File templating with Bash

Performs the application of given key/value pairs to a source template, with generated results written to an output file.

Functions applyTemplate accepts three arguments:

Source template file.
Target output file generated.
List of key/value pairs as an array.

Example

With the given source template:

PowerShell calling a function quirk

Something that trips me up often and a handy note to others. When calling a PowerShell function and storing the returned value, all output and the return value will be stored.

Example
Running

Example

Some code:

function myFunction() {

Unicode and the Byte order mark (BOM)

The byte order mark (BOM) is a Unicode character(U+FEFF) at the start of a text stream/file to signify the endianness and encoding used to a high level of confidence.

Examples

# utf-8
$ hexdump -C utf-8-bom.txt
00000000  ef bb bf 54 65 73 74 20  73 74 72 69 6e 67 20 e2  |...Test string .|
00000010 98 ba 0a |...|

Python function - is file binary?

Function which determines if a given file is binary.

Test is based on the following algorithm (similar to that implemented within Perl):

Empty files are considered text.
If not empty, read up to 512 bytes as a buffer. File will be binary if:
- Null byte is encountered.
- More than 30% of the buffer consists of "non text" characters.

	Set-StrictMode -Version Latest

	$HOSTED_ZONE_ID = "ABCDEFGHIJKLM"


	$changeRequest01 = New-Object -TypeName Amazon.Route53.Model.Change
	$changeRequest01.Action = "UPSERT"

	$changeRequest01.ResourceRecordSet = New-Object -TypeName Amazon.Route53.Model.ResourceRecordSet
	$changeRequest01.ResourceRecordSet.Name = "record01.domain.com"