Renaming files with mv without typing the name two times
Something like this isn't really necessary.  I do something like this (bash) all the time when I want to change a part of a filename (renames "foo-bar-baz.txt" to "foo-bar-quux.txt"):<p><pre><code>    mv foo-bar-{baz,quux}.txt
</code></pre>
You can have an 'empty' bit to add or remove something from the name (renames "foo-bar.txt" to "foo-bar-baz.txt"):<p><pre><code>    mv foo-bar{,-baz}.txt
</code></pre>
That will work with pathname parts as well (as in the linked demo video) if you include them in the command.<p>I guess the linked script is useful if you need to do some complex edits to the filename, since you can't usefully have more than one curly-brace-group for this use case.  But in that case honestly I'm fine just double-clicking the first argument to select, and then middle-clicking to paste, and then using the arrow keys to edit.