The Difference between GUID and UUID

GUID (Global Unique Identifier) and UUID (Universally Unique Identifier) are different implementations of the same idea. GUIDs and UUIDs are used as IDs (to identify) unique objects or records. These are very common in a big data environment where coordinating unique IDs in a central location is difficult to do. For practical considerations and nearly

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How to Generate a UUID in Java

UUID stands for Universally Unique Identifier. UUIDs are used as IDs (to identify) unique objects or records. An easy way to generate UUIDs in Java is to use the java.util.UUID class. Different variants and variant-versions exist for UUID objects. The methods of this class generally manipulate the Leach-Salz variant, although the constructors allow the creation

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How to Generate a UUID in Linux

UUID stands for Universally Unique Identifier. UUIDs are used as IDs (to identify) unique objects or records. An easy way to generate UUIDs in Linux is to use the uuidgen utility on the Linux/Unix command line. Generating UUID with uuidgen Simply executing uuidgen will generate a random UUID. Using the -t option will create a

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What is a UUID?

UUID stands for Universally Unique Identifier. UUIDs are used as IDs (to identify) unique objects or records. These are very common in a big data environment where coordinating unique IDs in a central location is difficult to do. Most values (if not all) in a UUID are generated randomly (depending on UUID version). UUID Format

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How to Set Number of Hadoop Reducers on Command Line

Setting the number of reducers for a Hadoop MapReduce job can be very important. Fortunately, there is an easy way to to this from the command line using the -D <property=value> option. Using -D Option on the Command Line A simple example of the -D option to set the number of reducers to 10: -D

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How to Delete Local and Remote Branches in Git

Working with branches is a core part of using Git. Often you will want to clean up and remove local and/or remote branches. Below are examples of how to delete local and remote branches in Git. Delete a Local Branch 1) git branch -d <branch-name> 2) git branch –delete <branch-name> The results of these two

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How to Copy local files to S3 with AWS CLI

AWS CLI has made working with S3 very easy. Once you get AWS CLI installed you might ask “How do I start copying local files to S3?” The syntax for copying files to/from S3 in AWS CLI is: aws s3 cp <source> <destination> The “source” and “destination” arguments can either be local paths or S3

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Copy all Files in S3 Bucket to Local with AWS CLI

The AWS CLI makes working with files in S3 very easy. However, the file globbing available on most Unix/Linux systems is not quite as easy to use with the AWS CLI. S3 doesn’t have folders, but it does use the concept of folders by using the “/” character in S3 object keys as a folder

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How to Sum Values in Awk

Knowing how to sum values in Awk can be extremely useful when working with data. Fortunately, it is very easy. Using variables in Awk will feel different than in other languages. There are no data types in Awk. A variable will either be considered a number or string depending on the context in which it

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How to Combine multiple Commits in Git

The ability to combine multiple commits in Git is a huge plus. Combining commits requires “rebasing” which will essentially rewrite the project history appending commits onto the last commit (by default) in a different branch, or even to an earlier commit in the same branch. Rebasing can have some damaging effects, so be careful when

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