dpkg -i /home/dnoob/Backports/octave-5.1.0/*.deb
(Reading database ... 353767 files and directories currently installed.)
Preparing to unpack .../liboctave7_5.1.0-4_amd64.deb ...
Unpacking liboctave7:amd64 (5.1.0-4) over (5.1.0-4) ...
Preparing to unpack .../liboctave7-dbgsym_5.1.0-4_amd64.deb ...
Unpacking liboctave7-dbgsym:amd64 (5.1.0-4) over (5.1.0-4) ...
Preparing to unpack .../liboctave-dev_5.1.0-4_amd64.deb ...
Unpacking liboctave-dev (5.1.0-4) over (5.1.0-4) ...
Preparing to unpack .../liboctave-dev-dbgsym_5.1.0-4_amd64.deb ...
Unpacking liboctave-dev-dbgsym (5.1.0-4) over (5.1.0-4) ...
dpkg: regarding .../octave_5.1.0-4_amd64.deb containing octave:
 octave breaks liboctave6
  liboctave6:amd64 (version 4.4.1-5) is present and installed.

dpkg: error processing archive /home/dnoob/Backports/octave-5.1.0/octave_5.1.0-4_amd64.deb (--install):
 installing octave would break liboctave6:amd64, and
 deconfiguration is not permitted (--auto-deconfigure might help)
Preparing to unpack .../octave-common_5.1.0-4_all.deb ...
Unpacking octave-common (5.1.0-4) over (5.1.0-4) ...
Preparing to unpack .../octave-dbgsym_5.1.0-4_amd64.deb ...
Unpacking octave-dbgsym (5.1.0-4) over (5.1.0-4) ...
Preparing to unpack .../octave-doc_5.1.0-4_all.deb ...
Unpacking octave-doc (5.1.0-4) over (5.1.0-4) ...
Preparing to unpack .../octave-htmldoc_5.1.0-4_all.deb ...
Unpacking octave-htmldoc (5.1.0-4) over (5.1.0-4) ...
Preparing to unpack .../octave-info_5.1.0-4_all.deb ...
Unpacking octave-info (5.1.0-4) over (5.1.0-4) ...
Setting up liboctave7:amd64 (5.1.0-4) ...
Setting up liboctave7-dbgsym:amd64 (5.1.0-4) ...
dpkg: dependency problems prevent configuration of liboctave-dev:
 liboctave-dev depends on octave (= 5.1.0-4); however:
  Package octave is not installed.
 liboctave-dev depends on libreadline-dev | libreadline-gplv2-dev; however:
  Package libreadline-dev is not installed.
  Package libreadline-gplv2-dev is not installed.
 liboctave-dev depends on libhdf5-dev | libhdf5-openmpi-dev | libhdf5-mpich-dev; however:
  Package libhdf5-dev is not installed.
  Package libhdf5-openmpi-dev is not installed.
  Package libhdf5-mpich-dev is not installed.
 liboctave-dev depends on libgl1-mesa-dev | libgl-dev; however:
  Package libgl1-mesa-dev is not installed.
  Package libgl-dev is not installed.
 liboctave-dev depends on libblas-dev | libblas.so; however:
  Package libblas-dev is not installed.
  Package libblas.so is not installed.
 liboctave-dev depends on liblapack-dev | liblapack.so; however:
  Package liblapack-dev is not installed.
  Package liblapack.so is not installed.
 liboctave-dev depends on libfftw3-dev; however:
  Package libfftw3-dev is not installed.
 liboctave-dev depends on gfortran; however:
  Package gfortran is not installed.

dpkg: error processing package liboctave-dev (--install):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of liboctave-dev-dbgsym:
 liboctave-dev-dbgsym depends on liboctave-dev (= 5.1.0-4); however:
  Package liboctave-dev is not configured yet.

dpkg: error processing package liboctave-dev-dbgsym (--install):
 dependency problems - leaving unconfigured
Setting up octave-common (5.1.0-4) ...
dpkg: dependency problems prevent configuration of octave-dbgsym:
 octave-dbgsym depends on octave (= 5.1.0-4); however:
  Package octave is not installed.

dpkg: error processing package octave-dbgsym (--install):
 dependency problems - leaving unconfigured
Setting up octave-doc (5.1.0-4) ...
Setting up octave-htmldoc (5.1.0-4) ...
Setting up octave-info (5.1.0-4) ...
Processing triggers for libc-bin (2.28-10) ...
Processing triggers for man-db (2.8.5-2) ...
Processing triggers for hicolor-icon-theme (0.17-2) ...
Processing triggers for install-info (6.5.0.dfsg.1-4+b1) ...
Errors were encountered while processing:
 /home/dnoob/Backports/octave-5.1.0/octave_5.1.0-4_amd64.deb
 liboctave-dev
 liboctave-dev-dbgsym
 octave-dbgsym