ShellHere is an OS X Finder toolbar app that opens the current Finder location in Terminal. This version is a fork of Etresoft's ShellHere, which was inspired by Marc Liyanage's OpenTerminalHere script. It's also similar to the popular Go2Shell but differs from these other implementations in a few key ways:

• opens Finder location in the current Terminal window/tab (if one exists) instead of opening a new window
• beautiful, native-looking icon by Henrik Nyh, used with permission under the CC BY 3.0 license

Download the disk image here and drag ShellHere to your Applications folder. Then just drag it onto your Finder toolbar. On newer versions of macOS, you may have to hold down Command while dragging to the Finder toolbar. Look for the green plus sign before dropping it.

OS X 10.7 or greater is required. It should work all the way back to 10.5, but you'll have to download the sources and build yourself.