Is there a linuxsoftware suitable for this? Unfortunately VLC doesn't let me do that.
For actual scrubbing through a video, i.e. advancing frame by frame, this can be done with vlc. The feature can be accessed by pressing the 'e' key or using the button marked 'Frame by Frame' under View --> Advanced controls, then using the screenshot capabilities of vlc which by default can be activated by using Shift+s. As far as I can see this will not run backwards though.
There are a few other non-scrubbing options with MPlayer and FFmpeg. MPlayer is capable of outputting images either automatically or manually from a video clip and perhaps this would be helpful. Have a look here:
FFmpeg has similar capabilities but with vastly more options:
But certainly the only genuine scrubbing option, and that forwards only, was with vlc...
sudo apt install smplayer ) lets you go forward and back frame-by-frame with the . (dot) and , (comma) keys.
Make sure you have "mpv" selected as the "Multimedia engine". It's under Options -> Preferences, at the top of the "General" tab. If you have "mplayer" selected instead, you can step forward frame-by-frame, but not backwards.
In the same Preferences tab, you can enable screenshots, and configure path and filename.
The default key for taking a screenshot is S.
Unfortunaltely, there seems to be no way to display the current frame number (or the timecode) in the player. As far as I know, only Quicktime 7 does that, but it will not be available anymore after MacOS 10.14 (Mojave).