How can I randomize the lines in a file using standard tools on Red Hat Linux?

Question

How can I randomize the lines in a file using standard tools on Red Hat Linux?

I don\'t have the shuf command, so I am looking for something like a

Answer 1

Related to Jim's answer:

My ~/.bashrc contains the following:

unsort ()
{
    LC_ALL=C sort -R "$@"
}

With GNU coreutils's sort, -R = --random-sort, which generates a random hash of each line and sorts by it. The randomized hash wouldn't actually be used in some locales in some older (buggy) versions, causing it to return normal sorted output, which is why I set LC_ALL=C.

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Related to Chris's answer:

perl -MList::Util=shuffle -e'print shuffle<>'

is a slightly shorter one-liner. (-Mmodule=a,b,c is shorthand for -e 'use module qw(a b c);'.)

The reason giving it a simple -i doesn't work for shuffling in-place is because Perl expects that the print happens in the same loop the file is being read, and print shuffle <> doesn't output until after all input files have been read and closed.

As a shorter workaround,

perl -MList::Util=shuffle -i -ne'BEGIN{undef$/}print shuffle split/^/m'

will shuffle files in-place. (-n means "wrap the code in a while (<>) {...} loop; BEGIN{undef$/} makes Perl operate on files-at-a-time instead of lines-at-a-time, and split/^/m is needed because $_=<> has been implicitly done with an entire file instead of lines.)