The following things are good:
This is a quickstart, so let’s not waste any time. The first thing your going to need is a GPG Key, so fire up the terminal and from the command line, type:
$ gpg --gen-key
This will launch the GPG key-generation program. First you’ll be asked to select what kind of key you want: (1) DSA and Elgamal (default), (2) DSA (sign only), (5) RSA (sign only). If you want to sign and encrypt messages, DSA and Elgamal is what you want and is the default, so we’ll use that.
Next you’ll be asked to choose a keysize. A large keysize is more secure than a small one, but also takes longer for your computer to encrypt/decrypt data. The default value of 1024 is adequate, so we’ll use that. If you’re really paranoid, you can use 2048, which is currently gpg’s maximum.
You’ll then be asked to set an expiry date for your key. While expiry dates can be used for stronger security, you probably want your key to be valid indefinitely. Choose 0 (the default) to create a key that never expires and confirm your selection.
You need a user ID to identify your key. You’ll be asked for your Real Name, Comment and Email Address which will result in a user ID in this form: “Real Name (comment) <email@example.com>”. Go ahead an type in your user ID details and confirm your entry.
Finally you have to enter a passphrase. A passphrase is like a password, but is longer, can contain spaces, and is supposed to be impossible to guess. Think of a passphrase as a super-password. Use a long sentence, or a line from one of your favorite songs, spaces and punctuation included. Oh, and if you ever forget your passphrase, there is NO way to get it back.
All done? Congratulations! You now have a public and secret key in your keyring. To see all your keys, use the list-keys command:
$ gpg --list-keys
If you ever need to revoke this key (because, say, you forgot your long and difficult-to-guess passphrase), it helps to have a revocation certificate prepared. Right after creating a key is a good time to prepare a revocation, so let’s do it now.
$ gpg --gen-revoke packagethief > ~/revcert.asc
You’ll have to answer a few questions (the default answers are fine) and enter the passphrase you chose for your key. The above command will create your revocation certificate in the file revcert.asc. Now, keep in mind that if someone gets a hold of this revcert, they’ll be able to revoke your key and render all your encrypted messages unreadable. You probably don’t want this, so it’s a good idea to hide this somewhere OFF your computer. You could put it on another volume, save it to a disk and keep in somewhere safe, or just print it and keep it locked away in your filing cabinet. At the very least, you want to make sure that nobody except you can read it, so let’s change the permissions:
$ chmod u-w,go-r ~/revcert.asc $ ls -l ~/revcert.asc -r-------- 1 packaget packaget 260 Oct 23 10:30 revcert.asc
Now you (the owner) are the only one who can read the file. Note that we’ve even removed write permissions for the owner.
Since most folks use a GUI-based email client like Thunderbird or Mail.app, here are some add-ins that you can use with your mail client to provide GPG functionality. These make it really easy to use GPG with your mail, adding sign/encrypt options to the Compose window and automatic decryption for encrypted messages.
Signing an email message using your key helps prove that the message came from you. This isn’t the same as encrypting the message, but is a common way to assert the authenticity of the sender. Your message is still sent in plain text and anyone can read it, but they can also use your GPG signature to verify your identity. I tend to sign most of the messages I send.
Encrypting is another story. To encrypt a message, you need the public key of the person to whom you are sending the encrypted message. When you use someone’s public key to encrypt a message, only the person who has the corresponding secret key can decrypt it. So, if I wanted to send an encrypted message to ‘John’, I would need his public key.
To obtain your public key (a big block of ASCII characters that looks like garbage text), use gpg -a --export from the command line:
$ gpg -a --export packagethief
This will print your key to the screen (the -a option tells GPG to output in ASCII text). Sometimes it’s more useful to have this in a text file so you don’t have to copy/paste it. To do so, just redirect the output to a file:
$ gpg -a --export packagethief > ~/pubkey.txt
This will save your key in the file pubkey.txt in your home directory. You can now publish your key (say, on your website), so that others can use it to send you encrypted messages.
Until today, I didn’t even know you could do this. You change the passphrase for a key by editing it. Not everything is editable (for example, you can’t change your user ID), but changing your passphrase is the kind of thing you might want to do from time to time.
$ gpg --edit-key packagethief Command> passwd
You’ll be asked for your existing passphrase before you’ll be able to type a new one. To exit and save your changes, type quit at the prompt.
$ gpg --help-----BEGIN PGP PUBLIC KEY BLOCK----- Version: GnuPG v1.4.1 (Darwin) mQGiBENbnh4RBAC7s8cQhyDkow6IgfIYpkflFQ5lmK8Hlcm8AR3Jcg2IsltBY+ZG jU/GyEwBJEsyyYxSZjy3/DVOsHMg2MGNNXE6TH0FQhpHnwgMgz2WQuyupSOnWz3o 5AI5ozBLS8+8CO8yufez6VNDsMr2nSJpwDgqCb2AN82nCkXJwtVWmZkPXwCgiOSN fldP3ZtF6QyQXnrsCNxNUskD/jpLeCOk/VrZI2UJ8jKGMeyNZP7p/2CSo78ZpcYF uu6Jtgtnrm2+F77ST7F5FGKTlioqeEi7Fw7j1Ve318bKfIn3hHB9E643mf6oD8FC wb6ATIIsv2u50yqFt6k9F/oHnc6gddunTcM5ulX4+56dJXlFVL7c+PPsdkFsjLZY kOmAA/4iQ5kmt8Fuwsep2Gs7fCQ+Wn6GmiGNwLjj/AC1IWwHdhHygPtS4xGshzvu L5VEuxeA0/zwoEh1gNqAIe2SGFKysbXSmD8vnW+wvWJ0a9aAaCag8WiMQ4dYwKTy NYtHjcQBwON6uGzwslyawO5WfF0zQwNGgun/0t58P0rghs7YZrQ1SmVmZnJleSBI YXJkeSAoUGFja2FnZXRoaWVmKSA8cGFja2FnZXRoaWVmQGdtYWlsLmNvbT6IXgQT EQIAHgUCQ1ueHgIbAwYLCQgHAwIDFQIDAxYCAQIeAQIXgAAKCRCwvVj9bv2rJl/b AJ9M2QEdxTgRj/kgg4OreczVyBMeiACfb1llQoLM0n/dp0Cb9hGbNvrHpi+5Ag0E Q1ueJhAIAM6oQqDqkijWVSdl86PPWmV560yKUJ/hX1/OjOYKtVdbbNL6zXSTnu9Y oB0t4RUq7E3bFHXYYOv+ndHCONE8IKv8LD58KLaO9TshyUHHH5uE1qEy0WfsBV/I axNTETv8JYUr/kdgLMu2M/chpBmFgQEyXJBzN+iYNKmS6Py2th3xhAWmnNMtP4af sDK/CLbf+TXkOrTn8312SuRDBVs/M95DtUEBVp0WoYhj8OPAe5uOXld2j731y4A0 fnsnldaV+prHjIwmHECHelDgti7H1lI7UkyPr92zYLU2akKgmQ+TIszn+XeNcOI+ aimSKetADgGTy+A8iuI7t6RP/rOerPsAAwUH/2jNqxWexpvH5ZGwsWI2qBl5bghz ofzTp4yxa/dj6LuU6rLfO4Rvob0avWjy8d2+b5ABvXfRM2BkZWjGP4s8sKJ1lRUM pGfCw9N9ouraQMXyoG+R7/ZKQhECQipBRpm1l7T0VazQ/36RUEFBj2uEOoyv8H5H uQ/s0/FQBZX2YU49vQ7ujBiutbRdedomx3dYw3kPpI9axagjGfJBgMhMOxZa0Dt8 pXico+KYFsXu26L3bacl73vSvCiqVRZfkDC06TvelR6yx/OGzxHPo6kFtjcUYGV1 wAHwdphcKd8Fy3+Xmi/Onpq4sXlBSL9IG1EW+eBISurCNOzsT2It8OVhun6ISQQY EQIACQUCQ1ueJgIbDAAKCRCwvVj9bv2rJha9AJ4/FxF/ECoRvlV7w5MLVHnFv3PG tACff4IWVTIMlABOm+o6aVfYliUUHb4= =sLot -----END PGP PUBLIC KEY BLOCK-----
This blog is running the young and as yet unspoiled typo blogging package. Just when it seems like the default theme, Azure, is poised to become the new Kubrick, Typo is having a theme contest to catalyze an explosion of new, unique, and free designs. This is unquestionably a Good Thing.
This theme is called Scribbish. Installing it is easy. Assuming you’re in your typo directory,
$ cd themes
$ curl -O http://smg.textdriven.com/scribbish.tar.gz
$ tar zxvf scribbish.tar.gz
$ rm scribbish.tar.gz
You should now be able to select “Scribbish” under the “Themes” tab in the typo backend.
So far I’ve tested it in Safari 2.01 and Firefox Beta 1.5 on OS X, and Firefox 1.0.7 on Ubuntu 5.10 Breezy Badger. Does it work in Internet Explorer on Windows? If so, consider it submitted.
MySql ships with a program called mysqldump for dumping table definitions and data from a database.
Usage: mysqldump [OPTIONS] database [tables]
There are a several of [OPTIONS], but when I want a nice, compact dump that I can use to create a schema definition, I use the following:
$ mysqldump -dr schema.ddl some_db --compact --compatible=mysql323,no_table_options --add-drop-table
This command results in a fairly database-agnositic schema definition in schema.ddl. There are no comments, no proprietary table or field definitions, and no data. The first option, -d, tells mysqldump to skip the data; -r tells it to output to schema.ddl; the rest of the options are verbose.
Creating new databases from this schema is painless. First, use the mysqladmin program to create a new, empty database:
$ mysqladmin create another_db;
Next, use the mysql client to execute the sql from schema.ddl:
$ mysql another_db < schema.ddl
Notes: For all three programs (mysqldump, mysqladmin, mysql), you can specify a user/pass with -u someuser -p . The commands executed will run as this user. Oh, and the -p option needn’t take an argument—you’ll be prompted for your password if you omit it.)
kill without a strength indicator is liking asking someone politely to go unconscious, while kill with a “-9” is like hitting them with a steel pipe.
Today I came across FIGlet, a little program for making large letters (signatures, banners, etc.) out of plain text.
I think I always vaguely pictured computer nerds sitting around for days on end painfully positioning pipes and underscores to create these obscure pieces of internet art. Now I know better.
You can download and install FIGlet from http://figlet.org, but if you’re using a package manager you’ll probably find there’s a port for it.
I use Darwin Ports on OSX and installation was trivial:
$ port install figlet
Once FIGlet has been downloaded and installed, start it up by typing figlet at the CLI and then type whatever you want. Alternatively, pipe a file or the output of another command through FIGlet, or put your input right on the command line as an argument.
$ figlet Hello World!
Now, go get working on your signature.
You can use SSH Keys to avoid having to enter your password when you log in to a remote machine. Think of your key as being your computer’s unique thumbprint. When you ssh into another computer, your thumbprint is checked against a list of pre-authorized thumbprints and if a match is found, you’re allowed in—no password required.
If you’ve never done this before, you’ll need to create a DSA key pair (the thumbprint). You only need to do this once.
$ ssh-keygen -d
Just hit enter to accept the defaults, and leave the passphrase blank. Your public key will be saved to the file ~/.ssh/id_dsa.pub
Now that you have a key, all you have to do is copy it to the authorized_keys file on the machine you want to log in to.
$ scp ~/.ssh/id_dsa.pub username@example.com:~/.ssh/authorized_keys
Nice. Now you’ll be able to log in without your password, which is really helpful when you want to do things like schedule backups using rsync, or if you’re lazy.
Just don’t lose your laptop.
So, you’ve finished the TODO lists, the cookbooks, and the ubiquitous byob (build your own blog) demonstrations from the Rails tutorial canon, and you’re impressed enough to begin building your first real-life Ruby on Rails application. It’ll be easy, you think. One hour—tops. Just like in the movie.
I bet at first, things are going smoothly. You’re generating controllers and models, you’re scaffolding, adding columns to the db, some validations here, some associations there, and life is good. You take a break, go have a cigarette, even, basking in the small victory of a rapid iteration. All that’s left to do now is get the user authentication system working… you know, that common thread that runs through the entire application. Easy, you think. You’ve read about that login generator that Tobias (xal) made. That’ll work.
Some hours later, after having gem install‘ed the login generator, gotten it working, realizing that you needed ACLs, poring over the wiki reading about implementing ACLs, and deciding to sit down with a cup of coffee and ActiveRecord’s api documentation, it hits you. You don’t know a lick of Ruby.
$ ./script/generate scaffold Person
The above will make a people controller and a Person model. This doesn't happen if you name your model and controller explicitly.$ ./script/destroy scaffold Person
development: adapter: mysql database: stickball_development host: localhost username: root password: secret test: adapter: mysql database: stickball_development host: localhost username: root password: secret production: development
/usr/lib/ruby/1.8/yaml.rb:119:in `load': parse error, you might have TABs. Spaces are the answer.$ ./script/console
and watch Rails load your environment up for you. Now you have access to all your Models and can do things like person = Person.find(:first) and anything else you might do in your Controllers.$ tail -f ./log/development.log
As you watch the ActiveRecord queries scroll past, think quietly to yourself—‘heh, I didn’t have to write any of that sql’. Isn’t that nice?
Hopefully these tips will help you as you continue to learn the Rails framework. And if things seem overwhelming, take heart—frameworks can be a difficult thing to learn. You sort of have to figure out where things go, what features are available to you by virtue of said framework, and how to code within the framework’s paradigm. Eventually, though, you’ll know the framework by heart. Really, it won’t take long.
Since switching to a Mac, I’ve drifted away from Firefox in favor of Safari and its tight integration with OS X. I still use FF for development (Safari has nothing like the Web Developer extension), it’s just not my default browser anymore.
Firefox 1.5 Beta 2 was released today, and after reading about the promise of better support for OS X, I downloaded it. After playing with it for about 3 seconds I have this to say: It’s better.
Alas, it still has problems fitting in with the OS X crowd, not all of which are the fault of the developers. One of the major bummers with Firefox on OS X is extension compatibility—a suprising number of my once-favorite extensions don’t work on the Mac. Tab Mix (an extension that adds advanced tabbed browsing preferences) is one such beast. But take heart, Mac users: Tab Mix Plus makes things right.
Tab Mix Plus is a spin on the original Tab Mix. Like Tab mix, it enhances Firefox’s tab browsing capabilites. While it may look similar it has a lot more features and added functionality like tab clicking options. Unlike Tab Mix however, it is Mac compatible. If you liked Tab Mix, you’ll love Tab Mix Plus.
It’s also (happily) compatible with the latest beta release. If you’re looking for better tabbed browsing on OS X, it might be worth a try.
David Harrison has created one deadly theme for Webmin
A completely new ‘Tiger-like’ look for Webmin featuring dropdown menus, AJAX search and high colour icon
Author of Beginning Rails and creator of the ever-popular Scribbish theme, Jeffrey Allan Hardy works at 37signals. He lives somewhere in the deep Canadian wilderness with his wife, his dog, and a cat.
