Preparing to unpack .../libtcl8.6_8.6.10+dfsg-1_amd64.deb ... Unpacking libtcl8.6:amd64 (8.6.10+dfsg-1) ... Selecting previously unselected package libotcl1:amd64. Preparing to unpack .../libotcl1_1.14+dfsg-4_amd64.deb ... Unpacking libotcl1:amd64 (1.14+dfsg-4) ... Selecting previously unselected package libtclcl1:amd64. Preparing to unpack .../libtclcl1_1.20-9build1_amd64.deb ... Unpacking libtclcl1:amd64 (1.20-9build1) ... Selecting previously unselected package libtk8.6:amd64. Preparing to unpack .../libtk8.6_8.6.10-1_amd64.deb ... Unpacking libtk8.6:amd64 (8.6.10-1) ... Selecting previously unselected package ns2. Preparing to unpack .../ns2_2.35+dfsg-3build1_amd64.deb ... Unpacking ns2 (2.35+dfsg-3build1) ... Setting up maven (3.6.3-1) ... update-alternatives: error: alternative link /usr/bin/mvn is already managed by maven dpkg: error processing package maven (--configure): installed maven package post-installation script subprocess returned error exit status 2