why no "ignore" command on git

Hello,

why does git don't have an "ignore" command, to ignore some files or directories all the time. In many project file structures you have IDE specified project files or directories which should not be tracked on git. All the time git says that you can add these files, this is not usable if you want to add many files with the "git add ." command. I read on some pages by a google search that you can create a ".gitignore" directory or something like that. But you had to do this manually.

why there is no "ignore" command on git?

best regards

Ralf