Tutorial by Examples: c

Windows proccess and service monitoring

Scollector will monitor any Windows processes or services specified in the configuration file. [[Process]] Name = "^scollector" [[Process]] Name = "^chrome" [[Process]] Name = "^(MSSQLSERVER|SQLSERVERAGENT)$"

Bosun • Scollector: Process and Service Monitoring

StackExchange.Exceptional collector written in Go with Metadata

The following Go file can be compiled into a continuous external collector that will query a MSSQL server database that uses the StackExchange.Exceptional schema. It will query multiple servers/databases for all exceptions since UTC 00:00 to convert the raw entries into a counter. It also uses the b...

Bosun • Scollector: External Collectors

Windows .NET process monitoring

Scollector can also monitor any Windows processes using the .NET framework. If no ProcessDotNet settings are specified it will default to just monitoring the w3wp worker processes for IIS. You can specify which applications to monitor in the configuration file. [[ProcessDotNet]] Name = "^w3...

Bosun • Scollector: Process and Service Monitoring

Accessing overridden default methods from implementing class

In classes, super.foo() will look in superclasses only. If you want to call a default implementation from a superinterface, you need to qualify super with the interface name: Fooable.super.foo(). public interface Fooable { default int foo() {return 3;} } public class A extends Object impl...

Java Language • Default Methods

Recovering from a lost commit

In case you have reverted back to a past commit and lost a newer commit you can recover the lost commit by running git reflog Then find your lost commit, and reset back to it by doing git reset HEAD --hard <sha1-of-commit>

Git • Recovering

Restore a deleted file after a commit

In case you have accidentally commited a delete on a file and later realized that you need it back. First find the commit id of the commit that deleted your file. git log --diff-filter=D --summary Will give you a sorted summary of commits which deleted files. Then proceed to restore the file b...

Git • Recovering

Recover a deleted branch

To recover a deleted branch you need to find the commit which was the head of your deleted branch by running git reflog You can then recreate the branch by running git checkout -b <branch-name> <sha1-of-commit> You will not be able to recover deleted branches if git's garbage col...

Git • Recovering

Getting Started with CardView

CardView is a member of the Android Support Library, and provides a layout for cards. To add CardView to your project, add the following line to your build.gradle dependencies. compile 'com.android.support:cardview-v7:25.1.1' A number of the latest version may be found here In your layout you ...

Android • CardView

Specifying namespaces

SQL Server 2008 WITH XMLNAMESPACES ( DEFAULT 'http://www.w3.org/2000/svg', 'http://www.w3.org/1999/xlink' AS xlink ) SELECT 'example.jpg' AS 'image/@xlink:href', '50px' AS 'image/@width', '50px' AS 'image/@height' FOR XML PATH('svg') <svg xmlns:xlink="http:...

Microsoft SQL Server • FOR XML PATH

Specifying structure using XPath expressions

SELECT 'XPath example' AS 'head/title', 'This example demonstrates ' AS 'body/p', 'https://www.w3.org/TR/xpath/' AS 'body/p/a/@href', 'XPath expressions' AS 'body/p/a' FOR XML PATH('html') <html> <head> <title>XPath example</title> &...

Microsoft SQL Server • FOR XML PATH

Establish a web socket connection

var wsHost = "ws://my-sites-url.com/path/to/web-socket-handler"; var ws = new WebSocket(wsHost);

JavaScript • WebSockets

Reducing values

5.1 The reduce() method applies a function against an accumulator and each value of the array (from left-to-right) to reduce it to a single value. Array Sum This method can be used to condense all values of an array into a single value: [1, 2, 3, 4].reduce(function(a, b) { return a + b; }); ...

JavaScript • Arrays

Logical connective of values

5.1 .some and .every allow a logical connective of Array values. While .some combines the return values with OR, .every combines them with AND. Examples for .some [false, false].some(function(value) { return value; }); // Result: false [false, true].some(function(value) { return value...

JavaScript • Arrays

Class lambdas and capture of this

A lambda expression evaluated in a class' member function is implicitly a friend of that class: class Foo { private: int i; public: Foo(int val) : i(val) {} // definition of a member function void Test() { auto lamb = [](Foo &foo, int val) ...

C++ • Lambdas

Newlines and control characters

A newline can be included in a single-string or double-quoted string. Note that backslash-newline does not result in a newline, the line break is ignored. newline1=' ' newline2=" " newline3=$'\n' empty=\ echo "Line${newline1}break" echo "Line${newline2}break" ...

Bash • Quoting

Double quotes for variable and command substitution

Variable substitutions should only be used inside double quotes. calculation='2 * 3' echo "$calculation" # prints 2 * 3 echo $calculation # prints 2, the list of files in the current directory, and 3 echo "$(($calculation))" # prints 6 Outside of doubl...

Bash • Quoting

Bitwise XOR (Exclusive OR)

The ^ operator will perform a binary XOR in which a binary 1 is copied if and only if it is the value of exactly one operand. Another way of stating this is that the result is 1 only if the operands are different. Examples include: # 0 ^ 0 = 0 # 0 ^ 1 = 1 # 1 ^ 0 = 1 # 1 ^ 1 = 0 # 60 = 0b1111...

Python Language • Bitwise Operators

File comparison

if [[ $file1 -ef $file2 ]]; then echo "$file1 and $file2 are the same file" fi “Same file” means that modifying one of the files in place affects the other. Two files can be the same even if they have different names, for example if they are hard links, or if they are symbolic links...

Bash • Conditional Expressions

File access tests

if [[ -r $filename ]]; then echo "$filename is a readable file" fi if [[ -w $filename ]]; then echo "$filename is a writable file" fi if [[ -x $filename ]]; then echo "$filename is an executable file" fi These tests take permissions and ownership into a...

Bash • Conditional Expressions

Numerical comparisons

Numerical comparisons use the -eq operators and friends if [[ $num1 -eq $num2 ]]; then echo "$num1 == $num2" fi if [[ $num1 -le $num2 ]]; then echo "$num1 <= $num2" fi There are six numeric operators: -eq equal -ne not equal -le less or equal -lt less than ...

Bash • Conditional Expressions