I just finished reading an article on Linux.com that talks about useful tools that a system administrator uses. This is a great article to read and glean if you are doing any system administration with your PHP development. At work and as a contractor I can only stress the importance that a developer needs to be familiar with system administration. You can check out the article here.
Here are some command line tools that i use almost on a daily bases to help out with system administration tasks.
- bash shell scripting
These are just some of the ones that I use. One point I would like to make is that by becoming familiar with additional commands you will start to become more proficient in your system admin tasks; obviously resulting in a sharper developer.