Download the Cyberduck zip file.
Install the Cyberduck program by dragging the Cyberduck file (not the Cyberduck zip file) from the Downloads window to the Applications folder.
Download Textwrangler from App store
The following steps you will do once and only
Click on the Cyberduck program.
On the menu bar, click Cyberduck to pull down the Cyberduck menu.
Click Preferences... to display the Cyberduck Preferences window.
Click the Editor button at the top of the Preferences window.
Click the drop-down arrow to select TextWrangler from the list.
If necessary, click the check box to place a check mark for Always use this application.
Close the Cyberduck Preferences window.