The `shuf` command in Unix/Linux-based systems is a command-line utility...

The shuf command in Unix/Linux-based systems is a command-line utility used to generate random permutations of input lines. It can randomly reorder lines from a file or from standard input, or even generate random numbers in a given range. Here's a breakdown of a general shuf command functionality:

1. Random Line Reordering:

   • If you have a file containing lines of text (e.g., file.txt), running shuf file.txt will output the lines in a random order.

2. Generate Random Numbers:

   • Using the -i option, you can specify a range of numbers to randomize. For example, shuf -i 1-10 will generate a random permutation of numbers between 1 and 10.

3. Selecting a Subset of Lines:

   • With the -n option, you can specify how many lines or entries to output. For instance, shuf -n 3 file.txt will randomly select three lines from file.txt.

4. Write to Another File:

   • The -o option allows saving the output to a given file. For example, shuf file.txt -o shuffled.txt will write the shuffled lines into a new file called shuffled.txt.

5. Random Seed:

   • When using the --random-source or --seed options, you can provide a seed to produce repeatable results (useful for testing).

Example:

shuf -i 1-100 -n 5

This generates 5 random numbers in the range 1 to 100.

In summary, the shuf command is a versatile tool for randomizing lines, generating random numbers, and selecting random subsets of entries either from files or a numerical range.