I have not done this for perhaps a decade or more. But apparently, things are still the same on Ubuntu 18.04:
sudo apt-get install build-essential
cpan
make install
install Bundle::CPAN
install App::GnuplotUtils
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...
To replace the string jeltsch.blogspot.com by the string mnm.no-ip.com/blog you can use perl:perl -pi.bak -e 's|jeltsch.blogspot.com|mnm.no-ip.com\/blog|g' *.html If you want to do a recursive replacement on a directory tree you can try:perl -pi.bak -e 's|jeltsch.blogspot.com|mnm.no-ip.com\/blog|g' `find jeltsch.org -name '*.html'`