Git Bash Completion

In the source directory under contrib/completions there is a bash completions directory. After sourcing that file you can then git <tab> <tab> and get all the git commands. You can also setup $PS1 to show you what branch is currently active with:

export PS1='[...]$(__git_ps1 "(%s)")[...]'

Make sure you use single quotes on the outside or it won’t work.

Encrypting Skype

Skype supposedly encrypts all communication between peers. Thing is, even if it’s encrypted, Skype still holds all the keys, so they could technically read anything that’s going through their system.

I found a plugin that lets you use Skype through Adium. Adium has Off The Record, which can then be used to encrypt Skype messages.

Here is a sample image of what the message looks like when intercepted by growl:

Skype message through Adium using OTR
Skype message through Adium using OTR

Truncating a file in use

Here’s a nice trick to zero out a file that’s in use:

cat /dev/null > /path/to/file

The reason for this is that if you simply remove a file that’s in use by some process on the system, the disk space will not be released until the process closes the file or terminates.

By cating /dev/null and redirecting it to the file, it magically guts out the contents of the file while keeping the same inode. The process that has that file open will continue writing to it without knowing any better, and the disk space will be released.

Update: A simple test using python to keep a file handle open showed me that while the cat trick zeros out the file, python keeps track of the last position written to within the file. The next time the python process writes to the file, you’ll end up with null bytes at the beginning of the file.

Renew DHCP via Terminal on OS X

To force a new DHCP lease on OS X you can use the following:

sudo ipconfig set en0 BOOTP; sleep 1; sudo ipconfig set en0 DHCP

It basically tells the ethernet device to use BOOTP, which gets rid of the current IP, then tells it to use DHCP a second later, which makes it request one again.

The device, above en0, should be changed to whatever device is to be updated.