How can I recursively delete all files of a specific extension in the current directory?

You don't even need to use rm in this case if you are afraid. Use find:

find . -name "*.bak" -type f -delete

But use it with precaution. Run first:

find . -name "*.bak" -type f

to see exactly which files you will remove.

Also, make sure that -delete is the last argument in your command. If you put it before the -name *.bak argument, it will delete everything.

See man find and man rm for more info and see also this related question on SE:

• How do I remove all .pyc files from a project?

find . -name "*.bak" -type f -print0 | xargs -0 /bin/rm -f

First run the command shopt -s globstar. You can run that on the command line, and it'll have effect only in that shell window. You can put it in your .bashrc, and then all newly started shells will pick it up. The effect of that command is to make **/ match files in the current directory and its subdirectories recursively (by default, **/ means the same thing as */: only in the immediate subdirectories). Then:

rm **/*.bak

(or gvfs-trash **/*.bak or what have you).