Linux Desktop – Yuanle's Blog

Intel AX200 bluetooth and wifi suddenly not working in Linux GNOME

sylecn — Sun, 04 May 2025 04:36:46 +0000

Symptom

You can’t toggle bluetooth on/off in GNOME applets.

rfkill list show bluetooth is not blocked.

bluetoothctl list show empty bluetooth controller list.

Solution

sudo modprobe -r btusb
sudo modprobe btusb

This will unload and reload btusb module, which may be able to fix the issue.

ref: [SOLVED] No bluetooth adaptater on AX200 / Kernel & Hardware / Arch Linux Forums

The Units Tool in Linux

sylecn — Sun, 23 Oct 2016 10:14:00 +0000

GNU Units can be used for many things. It is such a useful tool that I always install it on all Linux nodes.

Here is how I use it:

Convert network speed. ISPs and network device use bit per second, downloaders usually use byte per second.

units 1000Mbps MiB/s
; 119.21 MiB/s
units 100Mbps MiB/s
; 11.92 MiB/s
units 20Mbps MiB/s
; 2.38 MiB/s
units 4Mbps KiB/s
; 488 KiB/s

Calculate average download speed

units 800MiB/25min KiB/s
; 546.1 KiB/s

Convert hard drive space. Operating systems show GiB/TiB, while vendors use GB/TB.

units 1TB GiB
; 931.3 GiB
units 2TB GiB
; 1862.6 GiB

You can do calculation too. For example, if you have 24 16TB disks. Each data is stored in 3 replicas. At 80% capacity, you may store up to

units 16TB*24/3*0.8 TiB
; 93.13 TiB

Do time calculations

units '2 hour + 34 min + 1 day'
; 95640 s
units '2 hour + 34 min + 1 day' hour
; 26.6 hour
units 8mo weeks
; 34.8 weeks

Convert between tps and maximum possible total request per day

units 132tps req/day
; 11404800 req/day
units 132tps million*req/day
; 11.4 million*req/day

Convert between (single node) tps and average response time

units 132tps ms/req
; 7.5 ms/req

Convert foreign currency to local currency

units 39.99hkd usd
; 5.1 usd

units 500hkd/mo usd/year
; 765 usd/year

You may have notice some units are not built-in. Units allow you to define your own units very easily. Here is my ~/.units file:

word    !
words   1 word

rmb     !
cny     rmb
RMB     rmb
hkd     0.9393 rmb
aud     4.6608 rmb
usd     7.2959 rmb
eur     8.266 rmb
euro    eur
gbp     9.7282 rmb
GBp     0.01gbp
jpy     0.050583 rmb
sgd     5.5781 rmb
s$      sgd
inr     0.081919 rmb
rs      inr
mvr     0.4637 rmb
laari   0.01 mvr

request !
req     request
r       request
tps     req/s

BTC     64219 usd
bitcoin 1 BTC
btc     BTC

ETH     3490 usd
Ether    1 ETH
Ethereum 1 ETH
eth      ETH

# units 0K tempC
# units 0K tempF

core    !

jin     0.5kg

char    !

share   !

w       10000
yi      100000000

tx      !
transaction   tx
trans   tx

kwh     1000*watt*hour

You can define basic unit by using ‘!’, you can define unit alias, you can define conversion. See man units for more information.

Software that I use in Linux

sylecn — Sat, 23 Jul 2016 13:03:21 +0000

Updated On: 2016-10-23, 2025-05-05

Here are software that I use often in Linux.

General

name	area	my rate	my remarks
Firefox	browser	great	It may not be as fast as Chrome, but I like the option and prefer using it than Chrome. Also, Firefox Sync works inside China. Chrome web store and syncing requires extra effort in China.
Google Chrome	browser	great	A great browser. The device mode is much more accurate than Firefox’s Responsive Design View. Overall a nice browser.
mpv	media player	great	Best video player with Dolby Vision support. Support both mouse and keyboard controls.
VLC	media player	good	Cross-platform video player. GUI and settings are boring and not intuitive. Bad support for Dolby Vision.
Audacious	music player	good	Easy to use.
transmission	download	great	A reliable BitTorrent client. Intuitive UI. Also supports running on a server. 4.x is a great release that brings many improvements.
GIMP	image editing	good	Enough features for many use cases. UI is fine too once you get used to it.
ImageMagick	image processing	good	Convert image formats and resize images.
7-zip	archive	great	Easy to use.
Kodi (XBMC)	media center	good	Like Windows Media Center. Good for home theater. Some plugins are nice. Online programs is not fast in China though.
GNU Units	unit conversion	great	A very useful tool. You may check the Units Tool in Linux.
gThumb	photo viewer	good	Boring and works.
DigiKam	photo manager	average	Have great potential. But in current state, it is not top class.

Programming

name	area	my rate	my remarks
Emacs	editor	great	Like any good editor, it’s great once you get used to it.
git	version control system	great	Good for all textual files, not just for programming.
bugzilla	bug tracking	good	Battle tested. Excellent backward compatibility and long term maintenance. Who wants to upgrade a BTS every month?
Jenkins	continuous integration	good	Gets the job done. Remember to config git hooks to trigger a build automatically.
GoCD	continuous delivery	great	Manage your CD pipelines. Pipeline templates are useful. Build agents are flexible.
ipython with pandas	data processing	great	Dealing with data and plot is so much easier and pleasant.
postgres	database	great	When you need data safety.
redis	cache	great	When you need cache or a fast non-critical database.
sqlite3	database	great	I still use it sometimes when postgres is not available.
vpuml	UML diagram	good	The best UML diagram tool I have used. This is not free software though.

System

name	area	my rate	my remarks
Debian	operating system	great	Just use Debian stable, end of story.
gnome-terminal	terminal	great	Boring and works.
konsole	terminal	great	Boring and works.
VirtualBox	virtualization	great	Easy to use GUI. Acceptable performance. Well maintained.
clash	network	good	Not as stable as v2ray core or ss. But the rule engine is much easier to use.
gpg	sign and encryption	good	Secure. Integrates well in Emacs. Arcane to use in the command line.
ssh + tmux	sysadmin	great	Remote system administration should always run in screen or tmux.
rsync	network	great	All around good backup tool. I have a backup system based on rsync.
Syncthing	file syncing	good	Generally works well. May require manual intervention when synchronization stalls or file conflicts occur.
ffmpeg	media converter	great	Very capable video converter.
aria2	download	good	I use it when I want to use more than 1 thread to download from a single source. Otherwise, I use wget.
mutt	mail reading	good	Used when reading mail on a server. Yes, I agree all mail client s**ks.
salt	configuration manager	great	So much better than puppet. I use it to manage both workstation and servers.
parted/gparted	partition tool	good	Easy to use.
clonezilla	disk tool	good	When I want to do nasty things on partition, this is very useful.
lftp	ftp client	good	Supports ftp and sftp well. Support mirror a dir recursively, both for upload and download.
zerotier	network	good	Create a secure virtual LAN that connects all your devices.
wireshark	network	good	Capture and analyze network packets
CUPS	printing	good	Support printers.
OMD, CheckMK	monitoring	good	A monitoring solution based on nagios and check_mk.
smokeping	network	great	Monitor network quality. It records packet lose and latency and plot graphs on them.
remmina	network	great	Support Remote Desktop and VNC.
qrencode	graphic	great	Generate QR code easily.
nginx	network	great	My go-to web server and reverse proxy server.
samba	network	great	Sharing files to Windows and android clients. User document is not as nice. But once you get it, it gets the job done.
letsencrypt w/ acme.sh	network	good	Free SSL certs for HTTPS websites.

Office

name	area	my rate	my remarks
ibus	input method	good	Typing for non-English language. Boring and works.
rime-ice	input method	great	雾凇拼音. A well maintained Chinese word table and input method for use with rime input method.
abiword	office	good	When I want to do simple typesetting (page size, title indentation etc)
gnumeric	office	good	Gets the job done. Typing and cell/row resizing is not as good as MS Excel.
LibreOffice	office	average	Used when I need to open MS Office files, but don’t have access to MS Office. After all these years, LibreOffice usability is still BAD.
scribus	publishing	good	When layout is important and have to be controlled precisely, I use it.
GnuCash	finance	good	A good UI and feature set.
hledger	finance	average	Used this when GnuCash failed to run. I don’t like the concepts.

Old

Software that I have used before, but no longer use it now.

name	area	my rate	my remarks
rxvt-unicode	terminal	great	Boring and works.
v2ray	network	good	v2ray core is stable and support many protocols. Configuration is verbose though.
shadowsocks	network	great	Easy to config, easy to use. Connects you to the real internet in China.
trac	bug tracking	good	The default theme/design is too bad to look at daily.
Octave	math and engineering	good	Rarely used nowadays because python has a better toolset for calculation and drawing.
Vuze (was Azureus)	download	good	When I was using it, it’s good. It became bloated when I stopped using it.
mplayer	media player	good	Distribution for debian is poor. Compile it from source requires too many dependencies for my needs. Sometimes I got glitches or crash when rewind some video.
texlive	publishing	good	Used when I want to write something serious or when I’m bored and want to learn tex. I get less bored nowadays.
amarok	music player	good	I have used this player when I was using KDE in the early days. It’s not bad.
k3b	CD burner	good	Since I don’t burn CDs anymore. I no longer use it.
geany	editor	good	a lightweight editor I have used in the early days.
i3 (i3-wm)	window manager	good	Customization could be improved. Current feature set is good enough.
openbox	window manager	great	Before I get used to i3wm, this is what I use. Openbox with clearlooks view is nice.
openvpn	network	good	Good VPN software. Now replaced by wireguard.
filezilla	download	good	FTP client with GUI.
vagrant	programming	good	local VM orchestration tool. Nowadays I use salt to manage everything, vagrant doesn’t provide much value. Vagrant official box is not always good.
scim	input method	good	For some reason, in wheezy, scim-pinyin package is removed. That’s why I switched to ibus. Both SCIM and ibus is usable. But neither has great documentation.