Question: I'm trying to do a quick bulk search and replace for some common strings across a large number of source files. I'm doing this on a Mac, so I know it sometimes behaves a little differently. To start, I'm trying to get the list of all files recursively that contain the string I want to change:

`grep -rlF 'oldtext' .`

When the command runs, it appears to wait for stdin after displaying a list of files that contain the string I'm looking for. Control doesn't return to a prompt, and I can type and press enter with no real reaction from the terminal aside from the terminal showing what I type as I type it.

Am I calling `grep` incorrectly, or is there something about it running on a Mac that I'm not accounting for?

Answer: 
I've figured out this option is related to `Machine Learning Code Completion` plugin that is bundled with pycharm and is available via `Settings>Editor>General>Code Completion>Machine Learning-Assisted Completion>Rank completion suggestions based on Machine Learning`.
And this numbers are some sort of ranking.

Plugin doc says:

> 
> The plugin improves code completion feature by reordering of elements in the completion popup by ranking more relevant items higher using machine learning.
> 
> 
>
Those green ↑ or red ↓ has similar meaning as arrows used in foreign exchange rates:

[![enter image description here](https://i.stack.imgur.com/X9mIa.png)](https://i.stack.imgur.com/X9mIa.png)

but instead of rise / drop in the rate, they show rise / drop in *applying them to your code*, and – consequently – the change of their position in the completion popup.

[![enter image description here](https://i.stack.imgur.com/8uZmt.png)](https://i.stack.imgur.com/8uZmt.png)