OTStats is a single binary that doesn't have additional components and doesn't need to be installed per se. On GNU/Linux though it's required to make the file executable. It also may be worth it to put it somewhere in $PATH, for instance, in /usr/local/bin or ~/bin (the latter may not be in the $PATH).
Before starting to use OTStats, you have to select "Path to directory with your OmegaT projects" by pressing button on the right from the field (it's right under Unique and Spaces checkboxes).
When a new project is selected, it has no project data.
Unlock settings (button with a lock), type in number and select units you are being paid for (Amount per _ _ _ Characters/Segments/Words), set amount and select currency.
For instance, if you are paid $10.00 for 1800 characters with spaces, you tick "Spaces", type in "1800" at "Amount per", select "Characters" from the dropdown list, then type "10", and either type in "USD" or select it from the dropdown list.
Then click "Save settings" button (the one with a green tick). The project will be calculated within 2 seconds.
Pay units and rates are set for each project individually. If pay units and rates are not set, you can not view statistics.
NOTE: If your rate varies depending on match %, you cannot use OTStats to get accurate financial information. But you can still use it to track your overall statistics.
To change settings for a project, you need to press "Unlock" button first. Once new settings are typed in, you need to apply them (the button with a green tick). Without unlocking your changed settings will immediately revert to their previous saved state.
You can see how much you get done over a period of time (within one session). To do so, press Timer button (the one with a watch). Result will be printed in a lower part of the window.
In order to obtain best performance of OTStats, your OmegaT Auto Save Project setting should be set to 10 seconds. OmegaT updates its statistics on each save, and OTStats reads and shows only what OmegaT produces.
One can run OTStats from the running instance of OmegaT. In order to do that, run_statistics.groovy script is needed.
Download the script and put it to OmegaT scripts folder.
If OTStats binary was put somewhere not in the $PATH, edit the second line of the script so that it specifies full path to the OTStats binary. When the script is invoked, OTStats will open with the current OmegaT project.
You can run OTStats on its own with or without OmegaT running simultaneously. To have the program show the statistics, you need to select the folder where your projects are found (i.e., not the OmegaT project folder, but its parent folder).
The program's only setting is the path where your OmegaT projects are found. It's stored in $HOME/.OTStats/root.ini
Information about project's pay units and rates is stored in each projects folder in a file named omegat/statsini.txt
OTStats is capable of writing reports that can be used for invoices. There are two buttons: "Report" and "Append report". The reports are semicolon-delimited UTF-8 encoded csv files (even if extension may make you think otherwise).