Monthly Archives: December 2006

Editors Tech

vim’s sweet moves

December 22, 2006 – 9:00 am

Lately, I’ve been spending a lot of time editing books for my company, Guru Labs. Because of this, I’ve come to really appreciate the power of vim, and some of it’s very intuitive functionality. Many of you probably have much more experience with vim than I do, but I’d like to share some of the cool things I’ve recently learned while using vim.

Most of these commands involve command mode. If you are unclear what command mode is, you can find the documentation at http://www.vim.org/. Anyway, here’s the command I like to use:

  • :cd /path/to/where/my/files/reside – the :cd command allows you to change directory to somewhere more useful than where you currently are in the file tree. I find this useful when I am working on one project, then need to move away from that project to another one. I simply :cd /to/the/new/project/dir and then open the file from there.
  • :e filename – this command will simply open the requested file (if it exists) right into vim. If you need to abandon unsaved changes on the previous file, use :e!.
  • :pwd – this one may seem obvious to some, but did you know you can print your current vim working directory? Pretty neat I say.

These are some simple command to help you move about in vim. I am sure there are plenty more that you use, why not share them?

Cheers,

Clint

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Tech Tools

Cool rsync Action

December 20, 2006 – 9:48 am

Lately, I’ve been uploading very large iso files up to SoftwareFor.org for an up coming release of Software for Starving Students. Because of this, I’ve been reminded of a really cool feature of rsync.

rsync can, if you ask it to, update an individual file block by block. I am not completely familiar with the details, but I believe it has something to do with comparing small sections of a file. Hashing the small sections, and deciding whether that block actually needs to be transfered up to the remote location. Here’s my example:

On my box, I have one file SSS_WIN_2007.01.iso, it’s approximately 500MB. Initially, I transfered a slightly larger file (about 520MB) up to softwarefor.org via ssh. This process took about 3 hours on my qworst dsl connection. To me this is too long for anybody to really wait, but luckily for us, it only has to happen once.

After making some serious modifications to the interface of the iso, I needed to put the iso up again, but didn’t want to wait another three hours. In comes rsync to save the day. Because I had an older SSS_WIN_2007.01.iso up on softwarefor.org, and a newer one on my local box, I was able to upload only the changes (plus some negligible comparison overhead) by running the following command:

# rsync -avz --progress -e ssh SSS_WIN_2007.01.iso herlo@softwarefor.org:/path/to/old/.iso/

The resulf of running this command was a transfer time of approximately 30 minutes, where ssh would surely be over 2 hours again. I am glad I can save myself that much time. Here’s the output from the transfer itself.

herlo@softwarefor.org's password:
building file list ...
1 file to consider
SSS_WIN_2007.01.iso
521142272 100%  264.48kB/s    0:32:04 (xfer#1, to-check=0/1)

sent 105324111 bytes  received 142731 bytes  54294.38 bytes/sec
total size is 521142272  speedup is 4.9

Neat ain’t it?

Cheers,

Clint

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