On 09/06/2012 05:12 AM, Paolo Bonzini wrote: > I consider "shuf foo -o foo" (on a read-write file) to be insecure. > Besides, it works by chance
It's not by chance. shuf is designed to let you shuffle a file in-place, and is documented to work, by analogy with "sort -o foo foo". If we ever change "shuf" to use mmap, we'll make sure it continues to work in-place. I'm not sure what is meant by "insecure" here. Of course there are race conditions if other processes modify a file when "shuf" reads or writes it, but that's true for pretty much any program that reads or writes any file, including sed -i.
