Pacifist is a small program that attempts to do in Mac OS X what TomeViewer did in Mac OS 9 - it opens up .pkg installer packages and lets you install individual files out of them.
This is useful if you need to install just one file out of a package instead of the entire package (for example, if you deleted Sherlock and need to reinstall it, but not the whole operating system), if you experience bugs in Installer.app that mess up your symbolic links, or if you just like a little more control over the installation process.
Pacifist can also update prebinding information for files that you install to optimize their performance.
Pacifist opens Mac OS X .pkg package files, .dmg disk image files, and .zip, .tar, .tar.gz, .tar.bz2, and .xar archive files and allows you to extract individual files and folders out of them
Pacifist is also able to verify existing installations and find missing or altered files*, and also has the ability to examine the kernel extensions installed in /System/Library/Extensions to determine which ones were installed by Apple and which may have been installed by third-party installers.
Here are some key features of "Pacifist":