rmi1974

How to show differences between two Docker images

Courtesy of [github container-diff][1]

Prerequisite:

$ cd Downloads
$ curl -LO https://storage.googleapis.com/container-diff/latest/container-diff-linux-amd64

rmi1974

How to enable unauthenticated mounting of external disks using udisksctl

Courtesy of [reddit thread][1]

Create file /etc/polkit-1/rules.d/10-udisks2.rules with following content:

$ sudoedit /etc/polkit-1/rules.d/10-udisks2.rules

// See the polkit(8) man page for more information

rmi1974

How to automatically mount an encrypted volume at boot

Courtesy of [ask.fedoraproject.org][1]

NOTE: To have this work, one of your passphrases of your LUKS encrypted disk must be the same then your login password!

Prerequisite:

$ sudo dnf install pam_mount

rmi1974

How to spin-down hard drives with hd-idle

Courtesy of [github.com adelolmo hd-idle][1]

Prerequisite:

$ sudo dnf install golang

rmi1974

How to automatically enable and disable WiFi based on Ethernet connection with NetworkManager

Courtesy of [distroguy blog post][1]

cat << \EOF |sudo tee /etc/NetworkManager/dispatcher.d/70-wifi-wired-exclusive.sh
#!/bin/bash
export LC_ALL=C

enable_disable_wifi ()

rmi1974

How to optimize disk space usage with BTRFS

Enable zstd compression

For general overview see here: [BTRFS Compression][1].

Check zstd compression compression ratio using [compsize][2]:

$ sudo compsize $HOME

rmi1974

How to control VirtualBox from the command line

Some of the command line examples for interacting with Windows VMs require credentials. The examples assume they are exported in the current shell environment for convience:

export VBOXUSER=vboxuser
export VBOXPASS=vboxuser

rmi1974

How to find a binary's dependencies using dynamic linker

Courtesy of [exocus project on github][1]

You can invoke ld-linux with the LD_TRACE_LOADED_OBJECTS environment variable set to 1 and it will list all of the resolved library dependencies for a binary. For example, running

LD_TRACE_LOADED_OBJECTS=1 /lib64/ld-linux-x86-64.so.2 /bin/grep

rmi1974

How to Handle Secrets on the Command Line

Courtesy of [smallstep.com/blog][1].

The command line really wasn’t designed for secrets. So, keeping secrets secret on the command line requires some extra care and effort. The other day in my homelab I was configuring a TLS client certificate for a Grafana datasource. The intention was to write something I could run on a timer whenever the certificate is renewed. The command needed to:

1. Build some JSON with the renewed certificate and private key injected into it
2. PUT it to Grafana’s API to update the datasource configuration.

I thought I was being very clever when I wrote this lil' Bash pipeline:

rmi1974

How to display a directory tree with hashes truncated

alias truncate-hashes="sed -r 's/([a-f0-9]{8})[a-f0-9]{56}/\1.../g'"
tree ~ | truncate-hashes