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How to generate random numbers in shell?

Generating random numbers in shell can be done by utilizing the Bash $RANDOM function. This function will return a random integer between 0 and 32767 (inclusive). To make use of it, the syntax is:


The random number returned can be used directly as it is, or stored in a variable as such:


To limit the range of random numbers, use modulo, which is the remainder of dividing two numbers. For instance:

$(( $RANDOM % 10 ))

This will generate a random number from 0 to 9.

Another way to generate random numbers is by utilizing the command-line tool known as “shuf”. This tool is used to generate random permutations from a supplied list. As an example, to generate a random number between 1 and 10, the command would be:

shuf -i 1-10 -n 1

This will return a single random number in the specified range.

Overall, generating random numbers in shell can be accomplished through a variety of methods, depending on the specific requirements.

Can random () give 1?

Yes, it is possible for the random() function to generate the number 1, as random() typically produces a random floating-point number between 0 and 1. While it’s not as likely for it to generate a 1, since it is random, it is certainly possible.

Furthermore, it is possible to scale the output of random() to other numbers, such as integers. For example, to generate a random integer from 1 to 10, you could use int(random * 10) + 1. As you can see, the number 1 is a valid possibility in this case.

What is the formula to generate random numbers?

The formula to generate random numbers is a set of instructions used to produce unpredictable results, often referred to as true randomness. These instructions take input from a variety of sources (e.

g. , timing of keystrokes, mouse movements, thermal noise, etc. ) and use algorithms to mix these inputs together to produce a random output. Different methods may also be used to create different types of random numbers, including integers, decimals and boolean values.

By combining multiple concepts, it is possible to generate different types of random numbers and create a wide variety of results. Simple algorithms such as the Linear Congruential Generator (LCG) or Blum Blum Shub (BBS) are often used to create random numbers.

The LCG works by calculating a new seed from the previous one by multiplying by a constant and adding another, producing a pseudorandom result. In contrast, the BBS utilizes a built-in mathematical equation to create a seemingly random pattern.

What are the variables $1 $2 $3 etc used for?

In Unix-like operating systems such as Linux, the variables $1, $2, $3, etc. are commonly referred to as positional parameters. These variables are used when executing a command inside a shell script and contain the values of the parameters passed to the script.

For example, if you run a shell script like “some_script arg1 arg2 arg3”, then $1 would contain the value “arg1”, $2 would contain “arg2”, and $3 would contain “arg3”. The $0 variable is a special variable that always contains the name of the script itself.

These variables are very useful in shell scripts because they allow the script to accept a variable number of parameters and act accordingly.

What is ‘$’ in Linux?

‘$’ in Linux is a command line symbol that is used to represent the command prompt. It is used as a marker to indicate where the user should type a command. It also indicates that the user has the necessary privileges to execute the command.

For example, when using the Linux command line, a user might type ‘$ ls’ to list the files and directories in the current directory. This would be an example of the ‘$’ symbol in action, indicating that the user has the necessary privileges to execute the command ‘ls’.

Additionally, it may be used in place of a username in commands that require authentication, such as ‘$ su’ to become the root user. In some instances, ‘$’ may also be used as a shorthand symbol to refer the user’s current working directory, such as in the command ‘$ pwd’, which prints the working directory of the user.

What is the purpose of the special variables $1 $2?

The special variables $1 and $2 are part of a feature in bash and other similar shells called Command Line Arguments. Command Line Arguments are parameters passed to a command or script when it is invoked, and the special variables $1 and $2 refer to the first and second parameters, respectively.

These special variables are useful when writing shell scripts. For example, if a script requires two pieces of information such as a username and password, the arguments can be stored in the variables $1 and $2, which can then be used in the script.

They can also be used to iterate over arguments, since you can incrementally increase the argument number to access each successive argument.

In summary, the purpose of the special variables $1 and $2 is to store the first and second parameters in Command Line Arguments, which can then be accessed and used in scripts.

What is variable value example?

A variable value example is when a data-point is assigned a value that can change. A great example of this would be the total cost of a shopping cart. Each item in the shopping cart will have a value assigned to it, and as items are added or removed, the total cost changes.

Another example of a variable value could be a customer’s account balance. With each purchase or debit, the customer’s account balance changes. These are just a few examples of how a variable value works.

What are the kinds of variables *?

Variables are data values that can change over time. They are the basic elements of any programming language and can be divided into four main types:

1. Primitive Variables: These are the most basic type of variables and usually consist of single values such as integers, strings, and booleans. They are generally used to store basic values and are not interfaced with any other methods or classes.

2. Composite Variables: These types of variables can contain multiple values, such as arrays and classes. Composite variables are used to store complex data with multiple elements, and they can be accessed by calling methods or accessing individual elements.

3. Reference Variables: These variables store the memory address of another variable. They are generally used to create aliases, which allow the same variable to be referenced without creating a duplicate copy in memory.

4. Constant Variables: These types of variables are also known as read-only variables as their values cannot be changed. They are used to store fixed values that should remain unchanged throughout the lifetime of the program.

All four types of variables are important for programming and understanding how a program works. Variables are essential for creating a working program and allow data to be referenced and manipulated at various points throughout a program’s lifetime.

What does $Random do in Verilog?

In Verilog, the $Random system task is used to generate random or pseudo-random numbers. This task is typically used for testbench purposes, such as for generating inputs for functional simulations or to create unintended sequences that can be used to test edge case behavior.

The syntax for the $Random task is $Random(variable, bit-width, maximum value). The variable is the result of the operation and must be declared before use. The bit-width is the number of bits used in the result, and the maximum value is the maximum limit of the result.

When the $Random task is invoked, a single random number is generated. As this task does not support port connections, the random number must be manually assigned to the port. To invoke the system task multiple times, a loop construct is used, this ensures the same random number is not computed multiple times and can lead to patterns in the data set.

However, the $Random task only generates pseudo-random numbers and is not truly random. To create a truly random number, the Verilog programming language has a built-in system called $urandom(). This system reads true random numbers from a file and assigns them when the task is called.

Is random () really random?

Whether or not random() is truly random depends on a few factors, including the programming language you are using and the algorithm that’s generating the random values. Generally speaking, most programming languages come with built-in functions or libraries that make it easy to generate random numbers.

Many of these functions rely on deterministic algorithms which use a seed value to generate pseudo-random numbers. While the numbers may seem random, they are not truly random as they can often be predicted by knowing the seed value used.

True randomness on computers is much harder to achieve. To generate true random numbers, many operating systems rely on the computer’s internal hardware such as keyboard timings, hard drive activity, or mouse movement, which are more unpredictable and therefore more difficult to predict.

Additional measures must be taken to ensure that these hardware sources of randomness are robust and secure, in order to avoid any issues with unintended bias or other security concerns.

Ultimately, “random” is a matter of perspective – it’s often impossible to know for certain if a given set of numbers are truly random or not. Due to factors such as potential bias in the number generator and the difficulty of achieving true randomness, the only way to ensure that the values generated by random() are truly random is to closely monitor the system used to generate them and employ various security protocols to guarantee their integrity.

What does the random () method do?

The random() method is a static method in the java. lang. Math class which generates a random double number between 0. 0 and 1. 0. This method returns a pseudorandom double type number greater than or equal to 0.

0 and less than 1. 0. The syntax of the random () method is as follows: random ().

The random () method is usually used to generate random numbers in various applications such as games, simulations, etc. The generated number is not truly random, as it is generated using a mathematical algorithm and is therefore a pseudorandom number.

However, the generated number is sufficiently random for most applications and it is considered a good practice to use random () rather than relying on linear congruential generators.

The random () method can be used in different ways depending on the type of random number that is needed. For example, if you need a random integer between 0 and 100, you can use the random () method to generate a double between 0.

0 and 1. 0, and then convert it to the desired range. The same can be done if you need a random double between two specific numbers.

In addition, the random () method can also be used in conjunction with other methods for a more sophisticated approach to random number generation. For example, if you want to generate random numbers that follow a normal distribution, you can use random () to generate the numbers, and then use a function such as the Box-Muller Transform to convert the random numbers to a normal distribution.

What does the function __ random do?

The function __random() is a built-in function provided by the Python language to generate a random number. This function will generate a random number within a specified range, or it can be used to create a random float value between 0.

0 and 1. 0. The range in which the random number should be generated can be specified by providing two parameters to the function, start and end.

It can be used to generate random numbers for a wide range of applications, such as rolling dice, Monte Carlo simulations, choosing a random element from a list, performing statistical sampling, and many more.

It can also be used to create pseudorandom numbers, which are numbers that appear to be random but are actually generated algorithmically and follow a specific pattern.

Random numbers are an essential building block in many modern computing applications and Python makes it easy to generate random numbers with this powerful and versatile built-in function.