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How to find Unused Amazon EC2 Security groups
...AWS CLI tool, I found an easy way to get what I need:
First, get a list of all security groups
aws ec2 describe-security-groups --query 'SecurityGroups[*].GroupId' --output text | tr '\t' '\n'
Then get all security groups tied to an instance, then piped to sort then uniq:
aws ec2 describe-instance...
Focus-follows-mouse (plus auto-raise) on Mac OS X
...defaults write org.x.X11 wm_ffm -bool true
Apparently there's a program called CodeTek Virtual Desktop that'll emulate it systemwide, but it costs $$ (and they never got a version out for OSX Leopard).
share
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What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
...bar', so loop runs once and
done # prints nothing (actually "")
var="foo bar"
for i in "${var}bar"; do # Expands to 'for i in "foo barbar"; do...'
echo $i # so runs the loop once
done
# foo barbar
Note that "${var}bar" in the second example above could also ...
How can I remove an element from a list?
...
I don't know R at all, but a bit of creative googling led me here: http://tolstoy.newcastle.edu.au/R/help/05/04/1919.html
The key quote from there:
I do not find explicit documentation for R on how to remove elements from lists, but trial...
Integrating MySQL with Python in Windows
...rrently, I would recommend using PyMySQL. It's pure python, so it supports all OSes equally, it's almost a drop-in replacement for mysqldb, and it also works with python 3. The best way to install it is using pip. You can install it from here (more instructions here), and then run:
pip install pymy...
Spring Java Config: how do you create a prototype-scoped @Bean with runtime arguments?
... its BeanFactory#getBean(String name, Object... args) method which states
Allows for specifying explicit constructor arguments / factory method
arguments, overriding the specified default arguments (if any) in the
bean definition.
Parameters:
args arguments to use if creating a prototype using expl...
Python's most efficient way to choose longest string in list?
...this", "does", "work"], key=len)) only returns "this" instead of returning all of the longest strings.
– Anderson Green
Jan 22 '14 at 0:55
...
Why is there a difference in checking null against a value in VB.NET and C#?
...I don't know yet". Then the comparison of 5 to "I don't know yet". is naturally "I don't know yet"; ie NULL. This has the additional advantage of mirroring the behaviour of NULL in (most if not all) SQL databases. This is also a more standard (than C#'s) interpretation of three-valued logic, as expl...
How to prevent gcc optimizing some statements in C?
...eeds. This has the advantage of just applying to a single function and not all functions defined in the same file.
Usage example:
void __attribute__((optimize("O0"))) foo(unsigned char data) {
// unmodifiable compiler code
}
...
Installing older version of R package
...
To install an older version of a package from source (within R):
packageurl <- "http://cran.r-project.org/src/contrib/Archive/ggplot2/ggplot2_0.9.1.tar.gz"
install.packages(packageurl, repos=NULL, type="source")
If this doesn'...