Tutorial by Examples: b

An environment variable pointing to the Bash startup file which is read when a script is invoked.

An array containing the full version information split into elements, much more convenient than $BASH_VERSION if you're just looking for the major version: ~> $ for ((i=0; i<=5; i++)); do echo "BASH_VERSINFO[$i] = ${BASH_VERSINFO[$i]}"; done BASH_VERSINFO[0] = 3 BASH_VERSINFO[1] =...

Shows the version of bash that is running, this allows you to decide whether you can use any advanced features: ~> $ echo $BASH_VERSION 4.1.2(1)-release

IRB means "Interactive Ruby Shell", letting us execute ruby expressions from the standart input. To start, type irb into your shell. You can write anything in Ruby, from simple expressions: $ irb 2.1.4 :001 > 2+2 => 4 to complex cases like methods: 2.1.4 :001> def method ...

Inside your layout, add a Login button with the following code: <com.twitter.sdk.android.core.identity.TwitterLoginButton android:id="@+id/twitter_login_button" android:layout_width="wrap_content" android:layout_height="wrap_content" and...

foo = "bar" foo[0] = "c" # Error Immutable variable value can not be changed once they are created.

foo = ("bar", 1, "Hello!",) foo[1] = 2 # ERROR!! Second line would return an error since tuple members once created aren't assignable. Because of tuple's immutability.

Hive-Hbase integration is supported since below versions. Hive: 0.11.0 HBase: 0.94.2 Hadoop: 0.20.2 CREATE TABLE hbase_hive (id string, col1 string, col2 string, col3 int) STORED BY 'org.apache.hadoop.hive.hbase.HBaseStorageHandler' WITH SERDEPROPERTIES ("hbase.columns.mapping&q...

Eventually, when you're ready to release a version of your code to production, you'll need a .jar file to distribute. Intellij makes building JARs quite easy. First, navigate to File -> Project Structure and click on Artifacts: Click on the + button, and select JAR -> From modules with dep...

You can set any function for debugging with debug. debug(mean) mean(1:3) All subsequent calls to the function will enter debugging mode. You can disable this behavior with undebug. undebug(mean) mean(1:3) If you know you only want to enter the debugging mode of a function once, consider t...

On systems using systemd, such as Fedora => 15, Ubuntu (Server and Desktop) >= 15.04, and RHEL/CentOS >= 7: systemctl status [servicename] ...where [servicename] is the service in question; for example, systemctl status sshd. This will show basic status information and any recent errors ...

There are some cases in mixins where there can be single or multiple arguments while using it. Let's take a case of border-radius where there can be single argument like border-radius:4px; or multiple arguments like border-radius:4px 3px 2px 1px;. Traditional with Keyword Arguments mixing will be l...

You can build the cross-platform "Hello World" C++ code, using Scons - A Python-language software construction tool. First, create a file called SConstruct (note that SCons will look for a file with this exact name by default). For now, the file should be in a directory right along your h...

Attributes are global state (*). If they were implemented in JavaScript they would look something like this // pseudo code gl = { ARRAY_BUFFER: null, vertexArray: { attributes: [ { enable: ?, type: ?, size: ?, normalize: ?, stride: ?, offset: ?, buffer: ? }, { enabl...

//all attributes $collection = Mage::getModel('catalog/product') ->getCollection() ->addAttributeToSelect('*'); //specific attributes $collection = Mage::getModel('catalog/product') ->getCollection() ->addAttributeToSelect('name'); //certain attributes are special...

To view difference between two branch git diff <branch1>..<branch2> To view difference between two branch git diff <commitId1>..<commitId2> To view diff with current branch git diff <branch/commitId> To view summary of changes git diff --stat <branch/com...

ValueConverted To StringConverted To NumberConverted To Booleanundefinded"undefined"NaNfalsenull"null"0falsetrue"true"1false"false"0NaN"NaN"false"" empty string0false" "0true"2.4" (numeric)2.4true"test" (non nu...

class base { }; class derived: public base { }; int main() { base* p = new derived(); delete p; // The is undefined behavior! } In section [expr.delete] §5.3.5/3 the standard says that if delete is called on an object whose static type does not have a virtual destructor: if the...

This is a basic in-app keyboard. The same method could be used to make just about any keyboard layout. Here are the main things that need to be done: Create the keyboard layout in an .xib file, whose owner is a Swift or Objective-C class that is a UIView subclass. Tell the UITextField to use t...

A Static variable declared locally is not destructed and does not lose its value when the Sub procedure is exited. Subsequent calls to the procedure do not require re-initialization or assignment although you may want to 'zero' any remembered value(s). These are particularly useful when late bindin...