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Golang private modules within a GitHub organization

You've got Golang modules within a private repository or an organization and would like to go get them.

For this example the GitHub organization will be spacely-sprockets.

Howto

Set GOPRIVATE (ideally placed in your .bashrc / dotfiles):

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Find latest non beta/RC release for Docker CLI

Using curl and jq to:

• Pull list of GitHub release tags.
• Filter out all that don't match vX.Y.Z (stripping beta/rc).
• Finally return just the first entry (latest tag).

curl --silent \

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Creating a 'run once' systemd unit

A template for a systemd unit which calls a script exactly once on startup and keeps unit status active after script exits.

Unit file placed in /etc/systemd/system and enabled with:

$ sudo systemctl enable runonce.service
$ sudo systemctl start runonce.service

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DynamoDB local quick usage guide

Running a local version of DynamoDB inside a Docker container.

Commands

$ docker pull amazon/dynamodb-local:latest
$ docker run --publish 8000:8000 amazon/dynamodb-local

# in another terminal

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Golang io.TeeReader() example

• Opening a source words file.
• Create a io.TeeReader(), writing read file chunks also to a gzip writer.
• Output source chunks as read and total bytes.
• Finally, output compressed bytes and total compressed size.

Output

$ go run main.go

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GitHub token validation regular expressions

Simple regular expressions to check if a given GitHub token could be valid.

Personal access tokens

Personal access tokens are exactly 40 hexadecimal characters in length.

^[0-9a-f]{40}$

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Backblaze B2 via rclone cheatsheet

• Create B2 remote
• Tasks
  • List buckets
  • Synchronize local files to bucket
  • Synchronize local files to bucket - checksum
  • Verify local files against bucket
• Reference

Create B2 remote

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VirtualBox create host-only interface and attach

A host-only network interface is created virtually in software which appears to the host system.

This interface can be attached to one or more VMs, allowing connectivity between those VMs and communication between the host system and VMs.

• Create & attach interface
• Configure Ubuntu guests
  • Ubuntu 18.04+
  • Ubuntu pre 18.04
• Reference

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Git correct a commit via --fixup

Initial commit state:

$ git log --oneline
733e2ff Second widget done
fb2f677 First widget done
ac5db87 First commit

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Modify DNS for Optus supplied Huawei B315 4G modem

The Huawei B315 modem supplied by Optus for the (now defunt) Vividwireless service is a workable but sadly rather crippled device, even down to the inabiilty to modify assigned DNS servers from it's DHCP server away from Optus DNS to something sane (Google DNS/Cloudflare/etc.).

This script should allow for the easy update of assigned DNS servers and has been tested with Google Chrome.

Usage

• Log into router web UI (e.g. http://192.168.0.1).
• From the same browser session, open the "web developer tools" pane.
• Drop the contents of dnsmodify.js into Console area - modifying ROUTER_URI, PRIMARY_DNS and SECONDARY_DNS to suit.
• Run the script, updated DHCP settings are pushed and modem will restart.