Ubuntu系统

New install:
gcc, ssh, git, ftp, curl, wget,
ffmpeg, vlc, texlive,
IDL, ssw

sudo apt install gcc
# gcc 7.4.0 (2019-11-13)

ffmpeg

sudo apt install ffmpeg
# ffmpeg3.4.6 (2019-11-13)

VLC:

sudo apt install vlc
# 

change MAC address

sudo ifconfig enp0s25 hw ether 08:9e:01:ba:03:4b

will result in network blackout
DO

sudo ifconfig enp0s25 down
sudo ifconfig enp0s25 hw ether 08:9e:01:ba:03:4b
sudo ifconfig enp0s25 up

ds9
Introduction:
https://packages.ubuntu.com/bionic/saods9
http://ds9.si.edu/doc/user/scripts/index.html

$ sudo apt install saods9
$ ds9
Error in startup script: can't find package xml
    while executing
"package require xml"
    ("x11" arm line 10)
    invoked from within
"switch $ds9(wm) {
    x11 {
    # set to absolute path so that if -cd command is used,
    # so we can still find our files
    set ds9(root) [file normalize [..."
    (file "/usr/share/saods9/library/ds9.tcl" line 178)

Solution for this error:

$ ldd `which ds9`
not a dynamic executable

Then, you must download from the official site ds9 ( http://ds9.si.edu/site/Download.html ) and install it. Firsr, untar the downloaded file

$ sudo tar xzvf ds9.linux_distribution.tar.gz
$ sudo mv ds9 /usr/local/bin
$ sudo chmod +x /usr/local/bin/ds9
$ds9

This steps were validated on 20 Mar 2020 by DY

Ref: https://superuser.com/questions/1361857/cant-find-package-xml-while-executing-xubuntu-16-04