Showing posts with label random. Show all posts
Showing posts with label random. Show all posts

Tuesday, August 25, 2009

Generating strong passwords

Sometimes we need to make up the password. Normally the password should be easy to remember but hard to guess. I show you how to generate strong passwords that are not easy to remember :). We'll use for this purpose /dev/urandom device, which generates random data. Suppose we want to generate 10 passwords, each 8 characters long. To achieve this we type:

$ cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -8 | head -10
lUrBzyuv
RuDq498i
mOzJMs4Y
s0lUpMZd
LmwuN6Sy
fubIOO6g
KKynsPs4
dFH4W0Ux
3JAbwJQD
PofhRhTS

The fold command breaks each line after n characters, so defines the length of the password, the head command shows first n lines so defines the number of passwords. The tr deletes (-d) all but specified (-c) characters. The idea comes from here.