To create secure passwords on command line linux/ubuntu provides the automatic password generator. On Debian based distributions such as Ubuntu and its derivates just type
apt-get install apg
The standard mode wants to get some user input (your old password) and then suggests pronounceable passwords.
Please enter some random data (only first 16 are significant)
(eg. your old password):>
The second mode uses random character generation - here one can choose the character sets.
To create a strong password with a length of 12 characters type
user@ubuntu:~# apg -x 12 -M SNLC
where the options are
S - generator must use special symbol set for every generated password.
N - generator must use numeral symbol set for every generated password.
C - generator must use capital symbol set for every generated password.
L - generator must use small letters symbol set for every generated password
Learn more on apg on its man page
Was this useful for you? Do you know other tools like this one? Just drop a comment on it.