Useful Commands

Convert images to a video

ffmpeg -r 30 -start_number 3455 -i _IMG%d.jpg -s 960X600 -pix_fmt yuv420p
  • -r 30: 30 frames per second
  • -s 960X600: resolution
  • -pix_fmt yuv420p: for OsX

youtube-dl video and extract audio file

youtube-dl --proxy socks5:// -x --audio-format mp3 youtube-url


  • WORKON_HOME: which directory your environments are created in
  • /usr/local/bin/ default location for its configuration file
  • mkvirtualenv test --python=python3: make a virtual environment ‘test’ with python3
  • rmvirtualenv test: remove a virtual environment ‘test’
  • workon test3 or lsvirtualenv -b test3: activate a virtual environment ‘test’
  • deactivate: exit current environment
  • more details: search engine
    • how to avoid globa packages
    • how to copy an environment

node && npm

npm complains: Error: Cannot find module 'process-nextick-args'

Uninstall node, brew uninstall node, then by this stackoverflow post:

sudo rm -rf /usr/local/bin/npm /usr/local/share/man/man1/node* /usr/local/lib/dtrace/node.d ~/.npm ~/.node-gyp 
sudo rm -rf /opt/local/bin/node /opt/local/include/node /opt/local/lib/node_modules
sudo rm -rf /usr/local/bin/npm /usr/local/share/man/man1/node.1 /usr/local/lib/dtrace/node.d

Just delete something, then brew install npm.

delve (dlv) tips

  • funcs [regexp] : get function list
  • call : call a function (in a newer a go version, dlv should be installed in the newer go version too)


ssserver -c /etc/shadowsocks/config.json

sslocal and ssserver are all from apt-get install shadowsocks.

WSL 2 && VMware switch

After enabling WSL 2 on Windows 10 insider preview, VMware virtual machine is disabled.
This is because collision between Hyper-V and VMware.

Turn on VMware

bcdedit /set hypervisorlaunchtype off

Turn on Hyper-V && WSL 2

bcdedit /set hypervisorlaunchtype auto