Tutorial by Topics: and

require Module::Name; # Require by name from @INC require "path/to/file.pm"; # Require by relative path from @INC use Module::Name; # require and default import at BEGIN use Module::Name (); # require and no import at BEGIN use Module::Name (@ARGS); # require and import with args at...

void (*signal(int sig, void (*func)(int)))(int); ParameterDetailssigThe signal to set the signal handler to, one of SIGABRT, SIGFPE, SIGILL, SIGTERM, SIGINT, SIGSEGV or some implementation defined valuefuncThe signal handler, which is either of the following: SIG_DFL, for the default handler...

Proc.new(block) lambda { |args| code } ->(arg1, arg2) { code } object.to_proc { |single_arg| code } do |arg, (key, value)| code end Be careful about operator precedence when you have a line with multiple methods chained, like: str = "abcdefg" puts str.gsub(/./) do |mat...

read.csv(file, header = TRUE, sep = ",", quote = """, dec = ".", fill = TRUE, comment.char = "", ...) read.csv2(file, header = TRUE, sep = ";", quote = """, dec = ",", fill = TRUE, comment.char = "", ....

Python provides both builtin methods and external libraries for creating, modifying, parsing, and manipulating dates and times.

Classes and Objects are used to to make your code more efficient and less repetitive by grouping similar tasks. A class is used to define the actions and data structure used to build objects. The objects are then built using this predefined structure. class <ClassName> [ extends <Par...

#include <stdio.h> /* Include this to use any of the following sections */ FILE *fopen(const char *path, const char *mode); /* Open a stream on the file at path with the specified mode */ FILE *freopen(const char *path, const char *mode, FILE *stream); /* Re-open an existing stream on the...

While everything in Node.js is generally done asynchronously, require() is not one of those things. Since modules in practice only need to be loaded once, it is a blocking operation and should be used properly. Modules are cached after the first time they are loaded. Should you be editing a modul...

SELECT column_1 [, column_2 ] FROM table_1 ORDER BY order_column LIMIT row_count [OFFSET row_offset] SELECT column_1 [, column_2 ] FROM table_1 ORDER BY order_column LIMIT [row_offset,] row_count "Limit" could mean "Max number of rows in a table". "Offset&q...

Classes and IDs make referencing HTML elements from scripts and stylesheets easier. The class attribute can be used on one or more tags and is used by CSS for styling. IDs however are intended to refer to a single element, meaning the same ID should never be used twice. IDs are generally used with J...

SELECT column_name FROM table_name WHERE column_name operator value SELECT column_name, aggregate_function(column_name) FROM table_name GROUP BY column_name HAVING aggregate_function(column_name) operator value

Positive lookahead: (?=pattern) Negative lookahead: (?!pattern) Positive lookbehind: (?<=pattern) Negative lookbehind: (?<!pattern) Not supported by all regex engines. Additionally, many regex engines limit the patterns inside lookbehinds to fixed-length strings. For example the p...

undef # False '' # Defined, False 0 # Defined, Has Length, False '0' # Defined, Has Length, False Perl does not have a boolean data type, nor does it have any true and false keywords like many other languages. However, every scalar value will evaluate to true or false when evalu...

Pipe operators, available in magrittr, dplyr, and other R packages, process a data-object using a sequence of operations by passing the result of one step as input for the next step using infix-operators rather than the more typical R method of nested function calls. Note that the intended aim of p...

svn copy [BRANCH-FROM-URL] [BRANCH-TO-URL] -m <COMMIT-LOG-MESSAGE> svn copy [^/PATH-TO-BRANCH-FROM] [^/PATH-TO-BRANCH-TO] -m <COMMIT-LOG-MESSAGE> As you might have noticed, we use svn copy command to create branches, tags and shelves (we'll skip mentioning tags and shel...

Bosun Templates can include graphs to provide more information when sending a notification. The graphs can use variables from the alert and filter base on the tagset for the alert instance or use the GraphAll function to graph all series. When viewed on the Dashboard or in an email you can click o...

Scollector can be used to monitor processes and services in Windows and Linux. Some processes like IIS application pools are monitored automatically, but usually you need to specify which processes and services you want to monitor.