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Linux shuf command - generate random permutations.

If you wanted to quickly decide whose turn it is to make the tea you can use shuf. To shuffle words passed to shuf in standard input use the -e option. To select more than one line change the number.

This limits the output to the number specified. To pick a random line from a file using shuf use the -n option. The shuf command shuffles the lines and outputs this to standard output. In the following example we have a list of cards in a file saved as cards.txt. The result will be printed to standard output. To shuffle the lines in a file using the shuf command pass a file, files or standard input to the command. It can also limit the number of results returned supporting selecting random lines from a file or data from a list.

If given a file or series of files it will shuffle the lines and write the result to standard output. The shuf command generates random permutations from input lines to standard output. Examples of shuffling the lines in a file, picking a random line and shuffling standard input.Įstimated reading time: 2 minutes Table of contents Last updated Saturday, Linux and Unix shuf command tutorial with examples Tutorial on using shuf, a UNIX and Linux command for generating random permutations.

If it is an issue, more information would be required to determine a robust seed expression.Linux and Unix shuf command tutorial with examples | George Ornbo We don't have sufficient information to make that determination. Successive or simultaneous runs could yield identical results. Nearly every awk srand implementation's default seed is the number of seconds since the epoch. With regard to all of the AWK suggestions, without knowing exactly how the script is to be used, it's possible that all of the recommendations are inadequate. Post updated at 06:28 PM - Previous update was at 06:26 PM. Probably no need to fix it since Scrutinizer's first example in post #5 is a correct implementation of the same approach. The second, the for-loop post-increment expression, can cause the algorithm to yield anywhere between 1 and 200 lines. The first, a typo of Z for B, always exits before selecting anything. Looks like there are a couple of bugs there.

Random shuffle text file