I am using the ranger terminal based file manager to navigate and view files.When I navigate to a folder which contains pdf files, and position the cursor on a PDF file ranger reads the file  and then displays it in its preview pane .My understanding is that the ranger program delegates to rifle the tasks of recognising what type of file it is - in this case PDFlaunching a program which handles that filetypeinstructing the program to load the file currently under the cursorI now want to open the file being previewed in the text based program that is rendering the preview in the above image.  However when I press l to launch ranger/rifle uses  evince, a GUI program.Looking infile: ~/.config/ranger/rifle.conf#-------------------------------------------# Documents#-------------------------------------------ext pdf, has llpp,     X, flag f = llpp $@ext pdf, has zathura,  X, flag f = zathura -- $@ext pdf, has mupdf,    X, flag f = mupdf -- $@ext pdf, has apvlv,    X, flag f = apvlv -- $@ext pdf, has xpdf,     X, flag f = xpdf -- $@ext pdf, has evince,   X, flag f = evince -- $@ext pdf, has atril,    X, flag f = atril -- $@ext pdf, has okular,   X, flag f = okular -- $@ext pdf, has epdfview, X, flag f = epdfview -- $@ext pdf, has qpdfview, X, flag f = qpdfview $@This configuration indicates that evince will be used when a file is opened but what program is being used to generate the preview?I am using Ubuntu 16.04
How do I find out what program ranger is using to preview a file?
ranger
According to the webpage, it uses pdftotext for pdf previews.  (You could read the source code to be certain).