rewriting history

https://www.kernel.org/pub/software/scm/git/docs/git-filter-branch.html

git filter-branch --index-filter 'git rm --cached --ignore-unmatch filename' HEAD

cron

git, ssh, and cron can be a fussy combination. When debugging crontab's that involve git and ssh, it's often helpful to wedge a small script between git and ssh:

#!/bin/bash
/usr/bin/ssh -vvv "$@"

If you're trying to use a non-default ssh key with git (e.g. for github) then this will help: http://help.github.com/multiple-keys/

dotfiles

You can store your "dotfiles" in git, too, which is especially great now that we do so much work inside virtual machines. There seem to be two schools of thought:

• make a git repo in $HOME and include/exclude the files that you care about (e.g. http://psung.blogspot.com/2008/06/managing-dotfiles-with-git-continued.html, http://www.charlietanksley.net/philtex/dotfiles-and-git-take-2/)
• make a git repo in a subdirectory and sync from there up to $HOME (e.g. https://github.com/ryanb/dotfiles)

I'm trying the first approach. It seems less complex.

Setting up a new machine looks like:

$ cd
$ git init .
$ git remote add caboteria ssh://user@host/path_to_repo/dotfiles.git
$ git fetch caboteria mitre:caboteria/mitre
$ git checkout -fb mitre caboteria/mitre

http://vcs-home.madduck.net/ - turns out there's a group of people that talk about how they've done this.

Proxy

Some firewalls stomp on the git protocol so if you want to clone using URL's that start with "git:" you'll need to use a proxy to tunnel the git protocol over a different protocol like ssh (assuming the firewall lets ssh through).

Add a few lines to your ~/.gitconfig to tell git to use a proxy by default but to talk directly to machines inside your firewall:

[core]
        gitproxy = "none" for "your-company-domain.com"
	gitproxy = git-proxy

Create a git-proxy executable file somewhere on your path (~/bin or maybe /usr/local/bin). Here's the contents of my ~/bin/git-proxy file:

#!/bin/sh
echo "proxy to $1:$2 via ec2" >&2
exec ssh ec2 nc "$1" "$2"

In my case "ec2" is a host on the public internet that I have set up passwordless ssh access to. You'll need to use a different host.

I usually don't like to have programs like this output anything, but in this case I emit one line because the proxy should run sometimes but not others so it's handy to see whether git has decided to run it or not.

The only downside of this is that you need to use fully-qualified domain names for machines in your corporate domain, because git uses the domain name to decide whether to use the proxy or not.