Select random lines from a file [duplicate]

Question

This question already has answers here:

What's an easy way to read random line from a file in Unix command line? (13 answers)

Closed 6 years ago.

In a Bash script, I want to pick out N random lines from input file and output to another file.

How can this be done?

Answer 1

Sort the file randomly and pick first 100 lines:

$ sort -R input | head -n 100 >output

Answer 2

Use shuf with the -n option as shown below, to get N random lines:

shuf -n N input > output