How to use the command 'shuf' (with examples)

The ‘shuf’ command is used to generate random permutations. It can be used to randomize the order of lines in a file, generate random numbers within a specified range, and more.

Use case 1: Randomize the order of lines in a file and output the result

Code:

shuf filename

Motivation: This use case is useful when you want to randomize the order of lines in a file. It can be helpful when conducting data analysis or when you want to create randomized lists or surveys.

Explanation:

• ‘shuf’: The command itself.
• ‘filename’: The name of the file you want to shuffle.

Example output:

Line 3
Line 2
Line 1

Use case 2: Only output the first 5 entries of the result

Code:

shuf --head-count=5 filename

Motivation: Sometimes you only need a subset of the randomized lines. This use case allows you to specify the number of lines you want to output, which can be useful when you have a large file and only need a small sample.

Explanation:

• ‘shuf’: The command itself.
• ‘–head-count=5’: Specifies that we only want the first 5 lines.
• ‘filename’: The name of the file you want to shuffle.

Example output:

Line 4
Line 2
Line 1
Line 5
Line 3

Use case 3: Write output to another file

Code:

shuf filename --output=output_filename

Motivation: In some cases, you might want to save the shuffled lines to another file instead of displaying them in the terminal. This use case allows you to save the output of the ‘shuf’ command to a specified file.

Explanation:

• ‘shuf’: The command itself.
• ‘filename’: The name of the file you want to shuffle.
• ‘–output=output_filename’: Specifies the name of the output file.

Example output: The shuffled lines will be saved to the specified output file.

Use case 4: Generate random numbers in range 1-10

Code:

shuf --input-range=1-10

Motivation: This use case is useful when you want to generate random numbers within a specified range. It can be helpful when conducting simulations, creating random passwords, or any other use case that requires random numbers.

Explanation:

• ‘shuf’: The command itself.
• ‘–input-range=1-10’: Specifies the range of numbers to generate.

Example output:

7
1
9
5
4

Conclusion:

The ‘shuf’ command is a powerful tool for generating random permutations. It can be used to shuffle lines in files, generate random numbers, and more. By understanding the different use cases and arguments of the command, you can effectively use it in your daily tasks, data analysis, and scripting.