Check out SARbian, new distro (based on Debian Linux) with all the freely and openly available SAR processing software.
https://eo-college.org/sarbian/#intro
Included software:
General SAR processing
SNAP
ASF Map Ready
pyroSAR
SAR polarimetry
PolSARpro
SAR interferometry
DORIS
SNAPHU (for non-commercial use only)
PyAPS
PyRAT
GIS
QGIS
GDAL
GRASS GIS
Misc
R (+R Studio, +R Shiny)
Python (+Gdal, +Pip2, +Pip3)