diff --git a/CMakeLists.txt b/CMakeLists.txt
index a3795b3e..16c6e80c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -484,7 +484,12 @@ if (JFJOCH_RUGNUX_ONLY)
 elseif (JFJOCH_VIEWER_ONLY)
     set(CPACK_COMPONENTS_ALL viewer)
 else()
-    set(CPACK_COMPONENTS_ALL jfjoch writer)
+    # rugnux is packaged separately from everything else, as "rugnux" rather than "jfjoch-rugnux"
+    # (see the DEB/RPM branches below). It is the offline analysis CLI: it links none of the
+    # hardware libraries and talks to no service, so a machine that only processes data can install
+    # it alone. Up to 1.0.0-rc.163 it rode inside the jfjoch-viewer package, which is why both
+    # branches below declare the file move.
+    set(CPACK_COMPONENTS_ALL jfjoch writer rugnux)
     if (JFJOCH_INSTALL_DRIVER_SOURCE)
         list(APPEND CPACK_COMPONENTS_ALL driver-dkms)
     endif()
@@ -605,6 +610,18 @@ elseif (EXISTS "/etc/debian_version")
     set(CPACK_DEBIAN_JFJOCH_PACKAGE_REPLACES "jfjoch-jfjoch")
     set(CPACK_DEBIAN_JFJOCH_PACKAGE_CONFLICTS "jfjoch-jfjoch")
 
+    # rugnux ships as plain "rugnux", not "jfjoch-rugnux": it is a separately named product (see
+    # docs/NAMING.md), the released tarball is called rugnux-<version>-..., and it is what a user
+    # types. Overriding the name is the only way to drop the CPACK_PACKAGE_NAME prefix.
+    set(CPACK_DEBIAN_RUGNUX_PACKAGE_NAME "rugnux")
+
+    # /usr/bin/rugnux moved out of jfjoch-viewer into this package. Breaks+Replaces, NOT Conflicts:
+    # the two packages are meant to be co-installable from 1.0.0-rc.164 on, and this only has to
+    # stop an OLD viewer (which still owns the file) from being unpacked alongside. Without it dpkg
+    # refuses with "trying to overwrite '/usr/bin/rugnux', which is also in package jfjoch-viewer".
+    set(CPACK_DEBIAN_RUGNUX_PACKAGE_BREAKS "jfjoch-viewer (<< ${JFJOCH_VERSION})")
+    set(CPACK_DEBIAN_RUGNUX_PACKAGE_REPLACES "jfjoch-viewer (<< ${JFJOCH_VERSION})")
+
     # Enable automatic shlib dependency discovery
     set(CPACK_DEBIAN_PACKAGE_SHLIBDEPS ON)
 
@@ -646,6 +663,22 @@ elseif (EXISTS "/etc/redhat-release")
     set(CPACK_RPM_EXCLUDE_FROM_AUTO_FILELIST_ADDITION
             /usr/src /usr/share /usr/share/dbus-1 /usr/share/dbus-1/services /usr/share/pixmaps /usr/share/applications)
 
+    # rugnux ships as plain "rugnux", not "jfjoch-rugnux" -- see the DEB branch above for why.
+    set(CPACK_RPM_RUGNUX_PACKAGE_NAME "rugnux")
+    set(CPACK_RPM_RUGNUX_PACKAGE_SUMMARY "Offline crystallographic data analysis for Jungfraujoch")
+    set(CPACK_RPM_RUGNUX_PACKAGE_DESCRIPTION
+            "rugnux processes a stored Jungfraujoch HDF5 dataset: spot finding, indexing, geometry
+refinement, Bragg integration, scaling and merging. It needs none of the acquisition stack -- no
+broker, no detector, no FPGA card -- so it can be installed on a machine that only processes data.")
+
+    # /usr/bin/rugnux moved out of the jfjoch-viewer package into this one. Conflicts against the
+    # OLD viewer only, and deliberately NOT Obsoletes: obsoleting jfjoch-viewer would uninstall the
+    # viewer, which still exists and is still wanted. rpm turns "-" into "_" in a package version
+    # (an installed release reads 1.0.0_rc.160), so the bound has to be spelled the same way or the
+    # comparison silently never matches.
+    string(REPLACE "-" "_" _jfjoch_rpm_version "${JFJOCH_VERSION}")
+    set(CPACK_RPM_RUGNUX_PACKAGE_CONFLICTS "jfjoch-viewer < ${_jfjoch_rpm_version}")
+
     # DKMS component scripts and requirements for RPM
     if (JFJOCH_INSTALL_DRIVER_SOURCE)
         set(CPACK_RPM_DRIVER-DKMS_PACKAGE_REQUIRES "dkms, gcc, bash, sed")