Menu
I want to shuffle the lines of a text file randomly and create a new file. The file may have several thousands of lines.
How can I do that with cat, awk, cut, etc?
592
Using the shuf Command The shuf utility is a member of the GNU Coreutils package. It outputs a random permutation of the input lines. The shuf command will load all input data into memory during the shuffling, and it won't work if the input file is larger than the free memory.
On modern Linux systems you can use the [UpArrow] and [DownArrow] keys to scroll through the display. You can also use these keys to move through the output: [Space] - scrolls the display, one screenful of data at a time.
Using '>>' with 'echo' command appends a line to a file. Another way is to use 'echo,' pipe(|), and 'tee' commands to add content to a file.
You can use shuf. On some systems at least (doesn't appear to be in POSIX).
As jleedev pointed out: sort -R might also be an option. On some systems at least; well, you get the picture. It has been pointed out that sort -R doesn't really shuffle but instead sort items according to their hash value.
[Editor's note: sort -R almost shuffles, except that duplicate lines / sort keys always end up next to each other. In other words: only with unique input lines / keys is it a true shuffle. While it's true that the output order is determined by hash values, the randomness comes from choosing a random hash function - see manual.]
98
Perl one-liner would be a simple version of Maxim's solution
perl -MList::Util=shuffle -e 'print shuffle(<STDIN>);' < myfile If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
