Encrypt many files simultaneously on windows with GPG public key

For instance, you need to encrypt all files in a folder, here is the short script which may accomplish this task:

for %%i in (C:\folder\*.bak) do gpg --encrypt --batch -r backup@localhost "%%i"

Where backup@localhost is an identifier of public key.

Ubuntu: DNS configuration + multiple IP addresses on one interface

/etc/network/interfaces:

auto eth0
 iface eth0 inet static
 address 192.168.47.15
 netmask 255.255.255.0
 gateway 192.168.47.1
 dns-nameservers 8.8.8.8

auto eth0:1
 iface eth0:1 inet static
 address 192.168.47.14
 netmask 255.255.255.0

auto eth0:2
 iface eth0:2 inet static
 address 192.168.47.16
 netmask 255.255.255.0

How to check if there are upgrades for your Cisco IOS

It is a good practice to check periodically for new versions of Cisco IOS because of security vulnerabilities. To do it you can use
 Cisco IOS Software Checker
On this page you just need to choose your IOS version,  based on the output of the command:

show version

For instance: 15.2(4)M1

After this the wizard will show you the list of possible updates for your IOS. Next step is to get these updates. It is not so easy as with Microsoft or Linux, you can't just download them. The easiest way is to ask  your Cisco supplier, they usually have access to all Cisco downloads.