rg is harder to type with one hand because it uses the same finger twice. :)
I guess if you use a rigid fingering system. I never bothered to learn that back in elementary school, so my fingering is ad hoc based on what I'm typing. To type "rg" (using QWERTY), I'd just bring my middle finger up to R while using my index finger for G. This would probably be a little slower than "ag" because my hand is more likely to already be in place to type the latter without movement ("home row"), but not as slow as reusing a finger would be. It's not something I'd have to think about; this is already what I do whenever I have to type "rg" as part of a word.
I'm curious whether an ad-hoc approach is more or less efficient overall. Fingering customized per word clearly has the potential to optimize finger movement, but my error rate is relatively high - mostly timing-related - which might be exacerbated by an ad-hoc system because there are more (and more complex) unfamiliar transitions between words.
Anyway, I upvoted you for mentioning typing. It might seem trivial - well, if you use a lot of custom aliases, it is trivial - but if a command runs fast enough (and ag is already very fast on small source trees), the time spent typing its name can become a significant bottleneck. The author of Pijul, for instance, a version control system meant to compete with Git, seems not to recognize this... the command is 'pijul', which is essentially impossible to type on QWERTY without reusing a finger at least once.
I'm now thinking about it too much to be able to type naturally, but I seem to use middle and index interchangeably for some keys depending on which key was just pressed / is next to be pressed.
... and I just noticed if I sometimes use different fingers from the "wrong" hand to type depending on context too! I've typed the letter Y using right-index, left-index and left-middle and left-index during the course of writing this post. I guess this is what learning to touch type without being actually taught buys you :)
I've been plateaued at a 110wpm avg (121 top speed) @ 10fastfingers for quite a few months now, so perhaps breaking some of these bad habits would help me get to the desired 140.
This is a really interesting point. If we're going to be typing commands frequently, it would make sense for them to be optimally efficient to type using QWERTY (and maybe other common keyboard layouts).
`ls` and `cd` are super easy to type.
...you can switch your keyboard layout back to qwerty straight after you've typed the rg command. :)