I install QGIS 2.8 in debian (linux) through nightly jessie (qgis testing) and I see that SAGA is not in processing toolbox, so I install saga gis software but still it doesn't appear in processing.
How do I run SAGA in processing toolbox?
This problem is resolved through the line commands:
sudo add-apt-repository ppa:johanvdw/saga-gis sudo apt-get update sudo apt-get install saga
But in my case (Debian Jessie) instead of
sudo add-apt-repository ppa:johanvdw/saga-gis I went to https://launchpad.net/~johanvdw/+archive/ubuntu/saga-gis and in Technical details about this PPA I choose Trusty version, copy the lines and paste in sources.list. It works!!!