$ Linux Command

Text

shuf

Generate random permutations of input lines.

shufflerandomsorttext

Additional Notes

shuf (shuffle) writes a random permutation of its input lines to standard output. It reads from files or standard input and produces output with lines in a random order. It can also generate random numbers within a range when no input file is provided.

The randomness is suitable for most non-cryptographic purposes. shuf is useful for randomizing playlist orders, sampling data, splitting datasets for training/testing, or any situation where you need to randomize line-based data.

Syntax

shuf [options] [file]
shuf -e [options] arguments...
shuf -i LO-HI [options]

Parameters

  • file: Input file to read from. If omitted or -, reads from standard input.
  • arguments: Literal values to use as input lines (with -e).
  • LO-HI: Range of integers to generate (with -i).

Common Options

  • -n, --head-count count: Output only the first count lines of the random permutation (sampling).
  • -o, --output file: Write output to file instead of standard output.
  • --random-source file: Use file as a source of random bytes (default: /dev/urandom or similar).
  • -r, --repeat: Allow output lines to be repeated (sampling with replacement).
  • -z, --zero-terminated: Use null bytes instead of newlines as line delimiters.
  • -e, --echo: Treat each argument as an input line.
  • -i, --input-range LO-HI: Generate numbers from LO to HI (inclusive).

Examples

shuf playlist.txt

Shuffle the lines in playlist.txt and print them in random order.

shuf -n 5 data.txt

Select 5 random lines from data.txt without repetition.

shuf -i 1-100

Generate the numbers 1 through 100 in random order.

shuf -e apple banana cherry

Shuffle the given words.

shuf -n 3 -r -i 1-10

Pick 3 random numbers between 1 and 10, allowing repeats.

shuf data.txt -o shuffled.txt

Shuffle lines in data.txt and save the result to shuffled.txt.

Practical Notes

  • Without -r, each input line appears at most once in the output.
  • Use -n to sample a subset of lines without shuffling the entire input.
  • For reproducible results, use --random-source with a fixed file.
  • shuf is part of the GNU coreutils package.
  • For large files, shuf reads the entire file into memory.