Make sure you do have Ubuntu 12.04 LTS installed from Digi Embedded Linux 5.x live DVD.
Digi Eclipse ESP was tested only with Ubuntu 12.04. Older or newer Ubuntu versions or other Linux distributions might work, but you are on your own for solving problems.
Download the debian Linux package from https://www.segger.com/jlink-software.html
and install it by double clicking the .deb file from the file explorer. On command line this would look like this:# cat /etc/issue
Ubuntu 12.04 LTS
# qapt-deb-installer jlink_5.2.6_i386.deb
(Reading database ... 161891 files and directories currently installed.)
Preparing to replace jlink 4.84.6 (using .../home/digi/jlink_5.2.6_i386.deb) ...
Unpacking replacement jlink ...
Setting up jlink (5.2.6) ...
SEGGER J-Link Commander V5.02f ('?' for help)
Compiled Oct 2 2015 20:53:24
DLL version V5.02f, compiled Oct 2 2015 20:53:21
Firmware: J-Link compiled Jul 30 2008 11:24:37 ARM Rev.5
Emulator has Trace capability
VTarget = 0.000V
Last updated: Aug 23, 2017