Ranger utility
The ranger utility is a text based file manager, written in Python, and it uses the ncurses library to provide an interface for the file system. The user interface is minimalistic and the navigation is very easy. It is available in most of the popular Linux distributions.
The utility can be installed in an Ubuntu system by the following command at the prompt: directory, and up and down arrow keys used to browse the current directory.
The column at the right extreme displays a preview of the file. The default programs are used to display files. The less utility is used to display a text file, zipped files are uncompressed and displayed, the PDF files are displayed as text files and the image files are displayed using coloured ASCII art, though the clarity may not be good.
Ranger also includes a command interface, which helps you execute commands and manipulate files from within it. Several other options and features can be found by using the man command or from online sources.