another one of my brains

If you can’t remember the command line arguments to rsync, take heart. Start with something like

rsync -av src dest

and work your way from there.

You can re-auto-indent (?) some text in Vim with =. (It works with ST2, as well.) This can save you a bunch of manual > and/or <.

It’s seems close to useless with Python, but otherwise it can be very useful.

I always forget this, so here is the most basic of basics.

Right now, you’re typing this:

ssh foo@home.bar.com

You’d rather type this:

ssh home

Add this to ~/.ssh/config:

Host home
    HostName home.bar.com
    User foo

ssh home should now work as expected.

It’s actually super easy to use git and ssh to pull repos between your machines. Pull is the operative word, though. More on that in a bit.

Create a repo on machine A, whose hostname for this example is desktop.local. We’ll clone from this repo at first.

mkdir -p ~/src/my-repo
cd ~/src/my-repo
git init

On machine B, hostname laptop.local, we clone the repo:

mkdir -p ~/src
cd ~/src
git clone ssh://desktop.local/~src/my-repo

Now your laptop has a copy of my-repo and pulls from desktop.local.

If we want to be able to pull from laptop.local, we’ll need to tell desktop.local about it.

git remote add origin ssh://laptop.local/~src/my-repo
git branch --set-upstream master origin/master

That should do you.

Now, you can set up a scenario where you push to a repo, but it will work differently. You won’t be able to work in that repo; it’s purely for pushing and pulling, not committing. That’s a bit like github except your stuff doesn’t have to be public, and is instead secured behind ssh on your private machine.

Sometimes you want to monitor what changes are happening to a file or the output of a command. The poor man’s way to do it is via something like

while true; do echo foo; sleep 1; done

Fortunately, there exists a simpler way:

watch -n 1 'echo foo'

It appears to ship with Linux, but not Mac OS 10.7. Homebrew has it, however.

Assumptions:

• You have a remote machine configured to listen for VNC connections on such as :5900.
• You can ssh into your remote machine.
• You (wisely) have not opened port 5900 in your firewall.
• You want to access your machine remotely over VNC.

Let’s tunnel.

Rationale

VNC is basically plain text, including any keystrokes you send. Authentication is weak compared to such as ssh. And to access VNC remotely you’d ostensibly have to open that port to the Internet.

With ssh tunneling, you don’t have to open a special port in your firewall for VNC. All authentication and subsequent traffic happens over ssh.

Set up the tunnel

Try this:

ssh -C user@myhost.com -L 5900:127.0.0.1:5900

Feel free to add -fNq to background ssh (so you can’t accidentally close a terminal window and lose it), -N so that it doesn’t run any commands, and -q so that it’s quiet.

This connects you to myhost.com, forwarding your local port (hence -L) 5900 to the remote port 5900.

Connect

Use your favorite VNC client, connecting to localhost, port 5900, and with whatever credentials you set up.

Anecdata: slow?

I’ve only tested this once or twice. It seems pretty slow! I can’t tell if it’s the quality of this connection or what. So maybe prepare yourself.

Example: I have a big ol’ PATH variable, necessarily : separated. I want to see each entry on a separate line. Here you go:

echo $PATH | tr ':' '\n'

Or if you’re feeling even more terse:

tr ':' '\n' <<<$PATH

tr is one of my blind spots, I’ll admit. I’m more inclined to reach for sed or awk, which are overkill for little jobs like these.