shuf

Text processing

Usage

shuf [file]

Prints its input lines in random order; it is GNU coreutils and absent on macOS, where the usual stand-in sort -R groups equal lines together.

Common flags

Flag	Meaning
-n	Print only N lines
-e	Treat the arguments themselves as the lines
-i	Draw from a number range, as in -i 1-100
-r	Allow the same line to come out more than once
-o	Write to a file instead of standard output
--random-source	Use a fixed source so the shuffle can be repeated

Examples

shuf -n 1 names.txt

Picks one line at random.

shuf -i 1-49 -n 6

Six different numbers between 1 and 49.

sort -R names.txt

The nearest thing on a machine without shuf.

These were built to be piped together. Three joined commands are usually shorter than one that does everything.

How to read this

Q. What does shuf do?

Prints its input lines in random order; it is GNU coreutils and absent on macOS, where the usual stand-in sort -R groups equal lines together.

Q. How do I type it?

shuf [file] — square brackets mark the parts you can leave out.

Q. How many flags are worth knowing?

6 are listed here; the full set is in man shuf. This command sits under Text processing.

man page: man shuf