Bash: echo to stderr
echo error >&2
Filetransfer using netcat
It's quite easy to share files using netcat.
Serve a file on a listening port:
cat myfile.txt | nc -l -p 1337
Connect to this port and download file:
netcat SERVERIP 1337 > myfile.txt
HackADay: Controlling power outlets using the Raspberry Pi
My plan was to control some power outlets(16 ampere) using any browser(for example with a mobile phone). I wanted to use electronics only and tried to avoid relays.
Tcpdump: capturing packets with specific tcpflags
Let's catpure for example only tcp-packets with syn or ack-flag set:
tcpdump "tcp[tcpflags] & (tcp-syn|tcp-ack) != 0"
BTRFS: monitoring raid errors
Guacamole: A clientless remote desktop gateway using HTML5
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Guacamole is a clientless remote desktop gateway using HTML5. It supports the following backends: VNC, RDP, SSH and Telnet. It really looks like a promising project to me
Static arp-cache on dhcp-servers
We can use static ARP entries on hosts or routers to reduce ARP-traffic or to prevent ARP-spoofing. For such entries we need pairs of MAC-addresses and IP-addresses. The same information we also need for static DHCP-entries on a DHCP-server. Why not combine?
Oneliner: Permutation using ruby
➜ ~ ruby -e 'puts %w[t o m].permutation.map &:join'
tom
tmo
otm
omt
mto
mot
Route to nowhere - Blocking attackers using Nullroutes
If someone attacks a linux-system, most administrator would block the ip-address of the attacker using iptables-rules. But there is another method to block the address of an attacker: nullroutes. A Nullroute simply directs to nowhere.
Monitoring memcached
memcachetop is a nice perl-script for displaying live stats from memcached. The author kept portability in mind, so it has not much dependencies and might run on many systems.