regenerate ssh host key on CentOS 7

after duplicate vm image, we need to regenerate sshd's host key, here is the steps:

rm -f /etc/ssh/ssh_host_*
systemctl restart sshd.service

it will regenerate all the necessary files to avoid the host identity warnings.

Failed Flash Player Installation on Mac

Ok, today I was trying to install Flash Player on My Mac Yosemite, but follow the adobe's web instruction always resulted failed install, so I dug a little more and finally solved my problem.

open your mac terminal type following:

cat ~/Library/Logs/Adobe_ADMLogs/Adobe_GDE.log

this will output Adobe's installer log, it tells you the actual flash player installer it downloaded, try to find a line like following:

01/09/16 10:01:54:482 | [INFO] |  |  |  |  |  |  | 76833 | The file to be downloaded is http://fpdownload.adobe.com/pub/flashplayer/pdc/20.0.0.267/install_flash_player_osx.dmg

now you know where to download the file, still in the same terminal window, use wget to download the dmg file.

wget http://fpdownload.adobe.com/pub/flashplayer/pdc/20.0.0.267/install_flash_player_osx.dmg

it will download the dmg file in your current folder, most likely your home folder, now use Finder to navigate to the dmg file and launch it and click the "Install Adobe Flash Player" icon in the mounted disk image.

good luck!