Chrome Revisited

In my first serious test of Mac Chrome back in August, 2010, it came up short compared to other popular web browsers. But Chrome has been evolving fast. And since Firefox 4.0 was just released, it seemed like the right time to run another informal comparison.

What a difference. Chrome has become more stable, faster, and has made huge strides in available and useful plugins. The plugin gap with Firefox was a glaring issue last time. As a web developer, Firefox was indispensable with the Firebug plugin, letting you drill into the CSS and JavaScript acting on individual DOM components. Chrome now has native developer tools that rival Firebug. I am also fond of the Awesome Screenshot plugin that allows you to capture and annotate a web page from within the browser.

While I have found Firefox 4.0 a nice improvement in looks and rendering speed, I have also found it leaks memory, more so on Windows than Linux or Mac. I can rarely make it through a day without the Windows version locking up. That may be an artifact of the slew of plugins I am running and not the Firefox core.

For the last couple of weeks, I have been using Chrome as my primary browser on all platforms and have been very pleased. Competition is a great thing and I am excited to see browsers evolving again after what seemed like a long period of stagnation.

Android G2 and iTunes music sync

Getting music from iTunes on a Mac onto an Android G2 smart phone was an easy task. Maybe it wasn't so easy with the first generation Android phones, but the G2 I purchased a couple of weeks ago came with everything I needed.

Connecting the phone to the Mac

My main Mac is a two year old MacBook. The G2 came with a USB sync cable and as soon as I attached it, it opened iPhoto to upload pictures just like a camera. But the G2 also displayed a screen to enable it as a USB disk drive. I enabled disk mode, then took a look at the mounted volume in Finder.

One of the icons on the Volume was DoubleTwist. When I double clicked it, it started downloading the latest Mac version of DoubleTwist. After installation, the DoubleTwist interface looked very much like iTunes. It allows you to automatically sync all music from iTunes or just selections.

Since I don't plan to listen to music often on the G2, I chose to only sync playlists. This only syncs the music required in each playlist. There are a lot of options in DoubleTwist and the integration was seamless.

Automating FTP

People frequently need to automate FTP sessions to upload or download files.
Most command line FTP clients, including the FTP client on the Mac, can automatically login to an FTP server by reading the .netrc file in the user home directory. Note that the FTP auto-login file starts with a dot in front of the name (dot netrc).

Syntax of the $HOME/.netrc

The .netrc file can contain more than one auto-login configuration. Each FTP server has a set of commands, the minimum being the login name and password. You can create as many machine sections as you need. Here is a generic example:

machine ftp.server.com
  login myuserID
  password mypassword

Very Important: .netrc permissions!
Since user IDs and passwords are stored in the .netrc file, the FTP client enforces permission checking on it. It must be set so that no groups and no other users can read or write to it. You can set the permissions on it with this command from the Terminal (from your home directory) once the file is created:
chmod 700 .netrc

Adding FTP commands in a BASH script
You can embed FTP commands in a BASH script to upload and download files.
For example, you could create a script file named ftpupload.sh:

#!/bin/bash
# upload a file
/usr/bin/ftp -i ftp.server.com <<ENDOFCOMMANDS
cd backupdir
cd subdir
put datafile
quit
ENDOFCOMMANDS

In this example, I added the -i switch when running FTP to prevent it from prompting on multiple file uploads/downloads, even though it is only uploading one file in the example. I also use the BASH HERE document feature to send commands to FTP. When the script is run, it will auto-login using the information in the .netrc file, change to the right remote directory and upload the datafile.

Scheduling the script with Cron
The last step is to get the BASH script to run unattended, say every day at 5:00 am. The old school UNIX way is to use Cron, but the fancy new Apple way is to use a launchd XML configuration. As long as cron is supported in OS X, I'll stick to the old school way. I leave the launchd configuration as an exercise for the reader.

Add these lines with the command "crontab -e", then save:

# automated FTP upload
0 5 * * * /Users/username/ftpupload.sh

Dumping a Postgresql database remotely with SSH

I ran into a rare problem recently with a large Postgresql database that was filling up the local disks of a server. The database was large, over 100 GB and about 300 million records. There was a lot of churn and it had not been vacuumed in a long time. When I manually ran a vacuum on it, there was not enough working disk space to complete the operation, creating a bind.

What I decided to do instead of using vacuum was to dump it to a remote backup location, then drop the database and restore it from the remote dump. I used SSH to run the remote commands.

Dump a remote Postgresql database to the local machine
ssh user@remote-database-server 'pg_dump database-name -t table-name' > table-name.sql

Restore a remote Postgresql database dump to the local database server
ssh user@backup-machine 'cat table-name.sql' | psql -d database-name

Note that the dump command is run from the backup machine and the restore command is run from the database server.

Also note the single quotes around certain parts of the command.

The Google Chrome experiment

When Google first announced their Chrome browser, packed with a revamped JavaScript engine (V8) and support for offline web apps, I thought I would give it a spin. The first couple of releases were for Windows and Linux -- no Mac version. Those early versions were a little clunky and appeared to offer no better performance than other popular browsers. So I moved on.

When the Mac version became available, it was a much more polished browser. Another theoretical selling point was that each tab ran as a separate process so one crashed tab would not crash the whole browser. I decided to give Chrome a serious work out on my Mac at home.

Things started out well enough and performance was good. I perused the help and learned some of the short cuts. After about three good weeks, something went wrong. I don't know if it was an update, a growing cache, or what, but it started slowing down. Then, it started having problems loading pages from web sites that worked fine in other browsers. It is possible that it even caused wireless network issues, though that is just speculation at the moment. I need to do some more research to see if the problems were related to Chrome.

For now, I am sticking with Firefox as my main browser on the Mac. I'll come back and try Chrome out after the next major release.

Finding IPs connected to your web server

On Mac OS X
note: this also shows outgoing connections from web browsers

Get all IPs connected to your web server:

netstat -nat | sed -n -e '/ESTABLISHED/p' | awk '{print $5}' | sed 's/\./ /g' | awk '{print $1"."$2"."$3"."$4}' | sort

Get all unique IPs connected to your web server:

netstat -nat | sed -n -e '/ESTABLISHED/p' | awk '{print $5}' | sed 's/\./ /g' | awk '{print $1"."$2"."$3"."$4}' | sort | uniq -c | sort -n

On Linux
Get all IPs connected to your web server:

netstat -ntu | sed -e 's/::ffff://g' | awk '{print $5}' | cut -d : -f1 | sort -n

Get all unique IPs connected to your web server:

netstat -ntu | sed -e 's/::ffff://g' | awk '{print $5}' | cut -d : -f1 | sort | uniq -c | sort -n

RIP RJD

The Last in Line