[em500]

If you're importing from command line tools, you might as well use the specialized `shuf` tool:

  shuf -i 1-$bignum

or for random numbers with replacement

  shuf -i 1-$bignum -r -n $bignum

These give you a sample of random integers. `shuf` is part of GNU coreutils, so present in most Linux installs (but not on macOS).

[fouc]

It's worth installing GNU coreutils on macOs All the command names are prepended with g, so `gshuf`

[jeffbee]

Nice yeah that's a good way. Generally the number 1 million is so small I see no reason to do this in any manner other than shell commands.