The default command line application for batch renaming files in Ubuntu 16.04 is called "rename":
rename 's/tk98i_/wt_tk98_/' *.tif
It uses Perl regular expressions with and the s/old/new/ syntax. The example above renames all files with the .tif extensions and replaces the th98i_ expression with wt_tk98_.
Here are some more examples: http://tips.webdesign10.com/how-to-bulk-rename-files-in-linux-in-the-ter...