The default JDK DNS cache policy TTL (time to live) value is -1 (caching forever).

Exec_Master_Log_Pos

The position in the current master binary file up to which the SQL thread has read and executed. The coordinates given by (Relay_Master_Log_File, Exec_Master_Log_Pos) in the master's binary log correspond to the coordinates given by (Relay_Log_File, Relay_Log_Pos) in the relay log.

awk '{s+=$1} END {print s}' mydatafile

Sometimes this is very handy ;)

(ie - netstat -an | grep ':PORT ' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n | awk '{gsub(/^ +| +$/,"")}1' | cut -f 1 -d ' ' | awk '{s+=$1} END {print s}')

To detach a screen session,  type "^a d" (that's "control-a" followed by a "d" for detach).

Very common question. Separates novice from junior.

#!/bin/sh user=$1 realm=$2 pass=$3 hash=`echo -n "$user:$realm:$pass" | md5sum | cut -b -32` echo "$user:$realm:$hash

How to create http digest credentials in lighttpd. This is so common that it looks like google failed to produce any results.

scp file.txt tom@o {hit-tab-key}

This is nice one - it can complete remote dirs also. /Thanks Tay/

`c' for bytes

once in a lifetime..

-Y Enables trusted X11 forwarding. Trusted X11 forwardings are not subjected to the X11 SECURITY extension controls

I haven't read this man page too it seems ;) Thanks Tay.

The Scunthorpe problem occurs when a spam filter or search engine blocks e-mails or search results because their text contains a string of letters that are shared by an obscene word. While computers can easily identify strings of text within a document, broad blocking rules will result in a false positive, causing innocent phrases to be blocked.

Some popular libraries such as the Spring JMS Template are known to use these anti-patterns. If you're using Spring JMS Template and you're getting poor performance you know why. Don't blame HornetQ! The Spring JMS Template can only safely be used in an app server which caches JMS sessions (e.g. using JCA), and only then for sending messages. It cannot be safely be used for synchronously consuming messages, even in an app server.