set dns under Windows:

  netsh interface ip set dns name="本地连接" source=static addr=42.120.21.30 register=PRIMARY
  netsh interface ip set dns "本地连接" static 42.120.21.30 
  
Generate /etc/shadow password:

  mkpasswd --method=md5 --salt=STRING PASSWORDSTRING
  
  $1$:md5 $2a$:Blowfish $2y$:Blowfish, with correct handling of 8 bit characters
  $5$:sha256 $6$:sha512
  
GNU find:

  #execute multiple command when found:
  find . -type f -iname "*" -exec sh -c "pwd; echo {}" \;
  #change file extension:
  find /the/path -depth -name "*.abc" -exec sh -c 'mv "$1" "${1%.abc}.edefg"' _ {} \;
  
xargs: