PDF to .txt conversion or .tif to .txt conversion

[James Austin]

Hi folks,

I am downloading some journal articles for my History Degree, and  
they are either PDF or TIF. They are not accessible with VO and  
Preview. I have downloaded a shell program called PDFTXT but I've  
never used a shell program before.

Does anyone have any other ideas on how to convert PDF to txt or .tif  
to .txt?

Thanks

James