Murky Swamp

Install Gentoo on Raspberry Pi 5

Sun, 04 Feb 2024 00:00:00 +0000

Installing Gentoo on Raspberry Pi can be easy, can be hard. There are pre-built images like GenPi64, but this is not under development anymore.

Another way to install Gentoo is to download the stage 3 file and install it like installing on normal PCs, except we need to download firmwares from official repositories.

I have written a wiki page to demonstrate how to install Gentoo on a raspberry pi 5, and it only takes 30 minutes.

https://wiki.gentoo.org/wiki/How_to_install_Gentoo_on_Raspberry_Pi_5

For more details, you can always go to Raspberry Pi Install Guide, which is a new page contains installation guides for all raspberry pi versions.

Install PostgreSQL 9.4 with Homebrew

Mon, 31 Oct 2016 00:00:00 +0000

Homebrew is a great tool on Mac to install 3rd-party softwares and unix softwares like libxml2, MySQL, Redis, etc. Today let’s install PostgreSQL 9.4 with it.

First, install it with Homebrew command:

 brew install homebrew/versions/postgresql94

And then, start postgresql service with following command:
```
 brew services start homebrew/versions/postgresql94
```
This command will make sure postgresql is running every time you restart your computer. If you just want to start it one time, you could try command: postgres -D /usr/local/var/postgres
Last thing you need to do is to create a superuser postgres:
```
 createuser -d -a -s -P postgres
```
After entering your password, you have a running postgresql now.

Use CLI to configure Wifi on debian for Raspberry Pi

Mon, 27 Jun 2016 00:00:00 +0000

Raspbian is a customized Debian on Raspberry Pi, and it’s almost same as Debian.

Thank god Raspberry Pi 3 builds with a wireless module, we don’t need to spend $10 on a USB wifi card.

This post talks about how to configure wifi on CLI mode.

Update /etc/network/interfaces and make sure it looks like below:

 auto lo
 iface lo inet loopback

 allow-hotplug wlan0
 auto wlan0

 iface wlan0 inet manual
 wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf

Create or update /etc/wpa_supplicant/wpa_supplicant.conf
```
 update_config=1
 network={
   ssid="Your Wifi Network"
   #psk="your password"
   psk=<encryped_passphase>
 }
```
Attention: wpa will never use plain password for connecting wifi, you need to passphase it and put it here.

Actually there’s a simple way to generate this file, just use command below:
```
 wpa_passphrase <your_wifi_name> <your_wifi_password> > /etc/wpa_supplicant/wpa_supplicant.conf
```
After this, just put update_config=1 in the first line of that file.
Restart OS and you will see your Raspberry Pi is already connected to Wifi

Install Raspbian image on Raspberry Pi 3

Sun, 26 Jun 2016 00:00:00 +0000

For SBC, a.k.a Single Board Computer, dd is our friend. Normally, this is the only tool we use to “install” OS.

Today I will take “Raspbian” for an instance. As you can see, Raspbian is debian for Raspberry Pi, and its latest version May 2016, released in 2016-05-27. Download link: https://www.raspberrypi.org/downloads/raspbian/

After unzipping it, we get a file named 2016-05-27-raspbian-jessie-lite.img.

OK, let’s get started.

Prepare MicroSD

My work environment is Mac OS X, so I just open Disk Utility, click on “Eject” button of my disk. Also, check device name on the right , which is some name like disk2 or disk3. Mine here is disk3.
Run dd

Open terminal, run below command:
```
 sudo dd bs=1m if=/path/to/your/2016-05-27-raspbian-jessie-lite.img of=/dev/rdisk<N>
```
Here, we must pay attention to /dev/rdisk<N>. If you get disk2 above, use rdisk2 here, and if you get disk3, use rdisk3.
Finish

After a while, dd puts the whole image into our MicroSD card, bad thing is there’s no output of dd, so we never know when it is done. Once it’s finished, all we need to do is to eject our card, and put it into Raspberry Pi and power on.

Use email to create tasks in Omni Focus 2

Thu, 16 Jun 2016 00:00:00 +0000

There’s no doubt that Omni Focus 2 is a great GTD tool on Mac, or even in every platform. Sometimes I just feel hard to collect tasks, cause they are everywhere.

Imagine you are surfing on the internet and saw a really good article, and wants to read it later, you can create a take immediately in Omni Focus 2, or put it in Pocket, which is another great app for collecting articles. But, what if hundreds of articles are there? I believe no one will add them one by one.

So I came up an idea to add them automatically. Thank god Omni Focus 2 supports adding tasks via email. To enable it, you need to visit https://manage.sync.omnigroup.com/manage/ and sign in/sign up, and click “Add an address” in section “Mail Drop to Inbox”. After that, you will get an email address like “username.xxxx@sync.omnigroup.com”.

When you want to create a task, you can just simply send an email to this address, email title will be the task title, and email body will be the task details. Task will be located in “Inbox”.

Why is this cool? I created an “ifttt” task: each time a rss feed has a new item, create a task in Omni Focus 2, then, I know there’s a new article for me read. :-D

P.S. You have to enable syncing in Omni Focus 2 to use this feature.

How should Evernote do right now?

Sun, 24 Apr 2016 00:00:00 +0000

A few years ago Evernote was the number 1 notes app all over the world, and everybody loves it.

We can see articles everywhere talking about how to use it to keep notes and organize your notes, and even create your own knowledge library.

But several years passed, what do we read now?

http://www.appinn.com/import-evernote-to-onenote/

A Chinese article about how to migrate Evernote notes to OneNote
http://www.appinn.com/evernote-to-apple-notes/

Another article shows how to migrate Evernote notes to Apple notes

Last word from these is really intersting, “Evernote, you should think about why pepople are trying to get rid of you!”

So I wanna give Evernote some advices and hope it would be great again, and provide us good services:

Remove 60M/month limit
Add Markdown support (you should listen to the community)
Focus on notes itself (I know you are working on this, but do it better)
Free offline notes (be nice to your users)

If Evernote can fix all these things I talked about, I think it still get a chance.

Use getopt to parse script parameters

Tue, 01 Sep 2015 00:00:00 +0000

There are 3 ways to parse parameters for your CLI written by bash: position based parameter, getopts and getopt. With no doubt, getopt is the most powerful one.

I will use db-helper command from killbill to show you how to use getopt.

The first thing you should know is getopt is not internal command for bash, if you want to use it, you have to make sure it is installed, and gnu-getopt is more powerful than bsd-getopt, which means, if you are using Mac OS X, you need to replace it with gnu-getopt.

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ARGS=`getopt -o "a:d:h:u:p:t:f:" -l "action:,driver:,database:,host:,user:,password:,test:,file:,port:,help" -n "db-helper" -- "$@"`
eval set -- "${ARGS}"
while true; do
  case "$1" in
    -a|--action) ACTION=$2; shift 2;;
    --driver) DRIVER=$2; shift 2;;
    -d|--database) DATABASE=$2; shift 2;;
    -h|--host) HOST=$2; shift 2;;
    --port) HOST=$2; shift 2;;
    -u|--user) USER=$2; shift 2;;
    -p|--password) PWD=$2; shift 2;;
    -t|--test) TEST_ALSO=1; shift 2;;
    -f|--file) OUTPUT_FILE=$2; shift 2;;
    --help) usage; shift;;
    --) shift; break;;
  esac
done

Next is to think about parameters you want to use. You can use short parameter name like -a, -d, or long parameter name like --action, --database. Also, you can use both.

Parameter can be a switch like --rm, or a value like --host.

Run psql without password

Tue, 01 Sep 2015 00:00:00 +0000

To run psql without prompting password, you need to create $HOME/.pgpass file like below with correct file permission 600:

# host:port:database:username:password
localhost:5432:*:postgres:postgres

Update it with corrent values and there you go!

Increase your disk size for boot2docker

Sat, 28 Feb 2015 00:00:00 +0000

You searched for this article, so I assume you know what boot2docker is and are using it. That’s good, so am I.

But how many times have you got errors like no space left when you tried to pull a new image and running a command with container? I’ll tell you what, there’s a way to increase your disk size.

Find ~/.boot2docker/profile or create one if you cannot find it. For Windows, try %USERPROFILE%/.boot2docker/profile. There’s a configuration called DiskSize, change it to any size you want.

Make the whole configuraion file look like:

# boot2docker profile filename: /Users/lxie/.boot2docker/profile
Init = false
Verbose = false
Driver = "virtualbox"
SSH = "ssh"
SSHGen = "ssh-keygen"
SSHKey = "/Users/lxie/.ssh/id_boot2docker"
VM = "boot2docker-vm"
Dir = "/Users/lxie/.boot2docker"
ISOURL = "https://api.github.com/repos/boot2docker/boot2docker/releases"
ISO = "/Users/lxie/.boot2docker/boot2docker.iso"
DiskSize = 32000
Memory = 2048
SSHPort = 2022
DockerPort = 0
HostIP = "192.168.59.3"
DHCPIP = "192.168.59.99"
NetMask = [255, 255, 255, 0]
LowerIP = "192.168.59.103"
UpperIP = "192.168.59.254"
DHCPEnabled = true
Serial = false
SerialFile = "/Users/lxie/.boot2docker/boot2docker-vm.sock"
Waittime = 300
Retries = 75

Destroy your existing boot2docker-vm by running boot2docker destroy, and then use boot2docker init to create a new one.

Enjoy your new environment!

Kill containers in Docker

Tue, 30 Dec 2014 00:00:00 +0000

After using Docker for a while, you may find out there are so many containers in stopped status, and they are not deleted. You can delete them one by one with docker rm, but we are developers, how can we bear this?

Thank god Docker provides a parameter named -q in docker ps command to just print container IDs on console.

Delete all stopped containers

docker rm $(docker ps -f status=stopped -q)
Delete all containers

docker rm -f $(docker ps -a -q)

Isn’t it cool? If not, make some alias for this, like alias drma=docker rm -f $(docker ps -a -q), that’s how it’s done!