In Ruby, the if statement looks like this val = 1 if val == 1 p "Equality Checked!" end And for if else val = 2 if val == 1 p "Equality Checked!" else p "Equality Unchecked!" end And for if, else if, else val = 2 if val == 1 p "Equality Checked!" elsif val == 2 p "Equality Middle Checked!" else p "Equality Unchecked!" end Also, remember that everything in ruby returns a value, so your if statement can return a value that could be stored in another variable. ...

Part of the operators we get introduced to when learning to program is Bitwise Operators, examples are: The Bitwise OR | (a single pipe character) The Bitwise AND & (a single ampersand character) The Bitwise XOR ^ (a single caret character) Each of these has its usage, a refresher can be demonstrated considering these two variables foo=1 and bar=0 For the bitwise OR(|) operator const foo = 1, bar = 0 console.log(foo | bar) -> 1 For the bitwise AND(&) operator const foo = 1, bar = 0 console.log(foo & bar) -> 0 For the bitwise XOR(^) operator const foo = 1, bar = 0 console.log(foo & bar) -> 0 This seems pretty basic until you understand it is not. ...

Since everything is an object in Ruby having a functionality that can duplicate objects is not a bad idea. Ruby ships with two methods for making copies of an object: the dup method and the clone method. In Ruby, all variables hold a reference to an object. In a case where a section of a code modifies an object that is not meant to be modified, it is ideal to make a copy of that object to be used in that section of the code, protecting the integrity of the copied object. ...

Usually, programming languages have methods for printing out variables. Ruby is not an exception. We will explore the 3 popular methods for printing variables in the Ruby Programming language. The print method The way print(var) works is basically converting its value to a string by calling the to_s method on the object(everything is an object in Ruby) before printing the value and returning nil to its caller. num = 123 print(num) # -> 123 => nil The print method can be easily used for concatenating strings ...

The error: tar (child): xz: Cannot exec: No such file or directory Is majorly an issue with the xz command not found on the host machine. To verify, run: whereis xz Fix To fix, use the installation command for your Linux distribution: sudo apt-get install xz-utils # Debian / Ubuntu sudo yum install xz # RHEL / CentOS sudo zypper in xz # OpenSuSE sudo pacman -S xz # Arch Linux Then untar again with: ...

A onliner for f in *.old; do mv "$f" "${f%.old}.new"; done How??? To change the name of a file on Linux/Unix use the mv command mv currentfilename newfilename If there is a file named aleemisiaka.old and want to rename to aleemisiaka.new We can store the filename to a variable with export FILENAME=aleemisiaka And use the variable name in the mv command mv "$FILENAME"$ "$FILENAME.new" This renames the file from aleem-isiaka.old to aleemisiaka.old.new To ensure we end up with aleemisiaka.new and not aleemisiaka.old.new we could use parameter expansion. ...

Going through Chapter 2 of CLRS, I was introduced to the concept of divide and conquer, which is a very interesting algorithm technique, and a popular example of the divide and conquer algorithm is merge sort. Merge sort has an Θ(nlgn) run time, which is very good for large inputs. When the input is sufficiently small enough, the algorithm has a worse run time compared to a sorting algorithm that completes in Θ(n^2) time. One of the exercises is to create an optimized version of the merge sort that runs the original merge sort algorithm for sufficiently larger inputs where it shines and to run insertion sort [ Θ(n^2) ] when the input size is sufficiently small enough. I have a solution for it on my Clio website, this post walks through the process for the solution. ...

To search through the man pages for some keywords, use the -k option. man -k [keyword] This shows a result of the commands, and routines that match the keyword with a one-line description of what they are about. man -k passwd shows all the possible entries for passwd in the manual pages. The apropos The man -k [keyword] command is similar to a help utility called apropos which is available both on Unix and Linux. See it as a shortcut. ...

There are many ways to get help as a Linux administrator, manual pages are one of them as they are always close - accessible via the terminal. The manual pages, called “man pages” is a local documentation and description of software packages, drivers, routines, and libraries on a Linux machine. To use it run man [command|library|routine|driver] and replace the command with the name of a command to find a manual. ...

Communication between service workers and the clients browser window can be achieved by simply doing: self.clients.matchAll().then((clients) => { clients.forEach((client) => client.postMessage({ msg: "Hello from SW" })) }) The variable self is a reserved keyword in a service worker context. It references the global scope of the current worker execution scope and has some useful properties. It is like the window object of a JavaScript browser context. In the above snippet, all the clients that run the service worker are loaded, then the .postMessage is called to send message directly to the original javascript runtime of the service worker. ...