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Comment by cratermoon | Hacker News Reader

Need some random data quickly?

dd if=/dev/urandom count=1024 bs=1 | base64

Need it to be in a particular subset of characters?

dd if=/dev/urandom count=1024 bs=1 |tr -dc 'A-Za-z0-9'

Note: if you're on a mac, its tr is kind of broken. Do export LC_ALL=C first.

I find head easier for these, replace the first part of your commands with

head -c 1024 < /dev/urandom

The shell redirection < can be removed too, since head supports specifying files [from manual page HEAD(1)]:

head [OPTION]... [FILE]...

That just prints a bunch of garbage characters for me. I tested it on mac and Ubuntu xenial. Maybe it works differently elsewhere.

You still need to pipe through base64, i.e.

head -c 1024 /dev/urandom | base64

You can specify LC_ALL= on the same line, right before tr. Here's another example of a password generator (without dd):

  LC_ALL=C tr -dc 'a-zA-Z0-9-_\$' </dev/urandom | fold -w 20 | sed 1q