Modifying replace string in xargs

Question

When I am using xargs sometimes I do not need to explicitly use the replacing string:

find . -name "*.txt" | xargs rm -rf

In other cases, I want to specify the replacing string in order to do things like:

find . -name "*.txt" | xargs -I '{}' mv '{}' /foo/'{}'.bar

The previous command would move all the text files under the current directory into /foo and it will append the extension bar to all the files.

If instead of appending some text to the replace string, I wanted to modify that string such that I could insert some text between the name and extension of the files, how could I do that? For instance, let's say I want to do the same as in the previous example, but the files should be renamed/moved from <name>.txt to /foo/<name>.bar.txt (instead of /foo/<name>.txt.bar).

UPDATE: I manage to find a solution:

find . -name "*.txt" | xargs -I{} \
    sh -c 'base=$(basename $1) ; name=${base%.*} ; ext=${base##*.} ; \
           mv "$1" "foo/${name}.bar.${ext}"' -- {}

But I wonder if there is a shorter/better solution.

Answer 1

The following command constructs the move command with xargs, replaces the second occurrence of '.' with '.bar.', then executes the commands with bash, working on mac OSX.

ls *.txt | xargs -I {} echo mv {} foo/{} | sed 's/\./.bar./2' | bash