generate pronounceable passwords
pwgen [ OPTION ] [ pw_length ] [ num_pw ]
The pwgen program generates passwords which are designed to be easily memorized by humans, while being as secure as possible. Human-memo‐ rable passwords are never going to be as secure as completely com‐ pletely random passwords. In particular, passwords generated by pwgen without the -s option should not be used in places where the password could be attacked via an off-line brute-force attack. On the other hand, completely randomly generated passwords have a tendency to be written down, and are subject to being compromised in that fashion. The pwgen program is designed to be used both interactively, and in shell scripts. Hence, its default behavior differs depending on whether the standard output is a tty device or a pipe to another pro‐ gram. Used interactively, pwgen will display a screenful of passwords, allowing the user to pick a single password, and then quickly erase the screen. This prevents someone from being able to "shoulder surf" the user's chosen password. When standard output (stdout) is not a tty, pwgen will only generate one password, as this tends to be much more convenient for shell scripts, and in order to be compatible with previous versions of this program.
-0, --no-numerals Don't include numbers in the generated passwords. -1 Print the generated passwords one per line. -A, --no-capitalize Don't bother to include any capital letters in the generated passwords. -a, --alt-phonics This option doesn't do anything special; it is present only for backwards compatibility. -B, --ambiguous Don't use characters that could be confused by the user when printed, such as 'l' and '1', or '0' or 'O'. This reduces the number of possible passwords significantly, and as such reduces the quality of the passwords. It may be useful for users who have bad vision, but in general use of this option is not recom‐ mended. -c, --capitalize Include at least one capital letter in the password. This is the default if the standard output is a tty device. -C Print the generated passwords in columns. This is the default if the standard output is a tty device. -N, --num-passwords=num Generate num passwords. This defaults to a screenful if pass‐ words are printed by columns, and one password otherwise. -n, --numerals Include at least one number in the password. This is the de‐ fault if the standard output is a tty device. -H, --sha1=/path/to/file[#seed] Will use the sha1's hash of given file and the optional seed to create password. It will allow you to compute the same password later, if you remember the file, seed, and pwgen's options used. ie: pwgen -H ~/email@example.com gives a list of possibles passwords for your pop3 account, and you can ask this list again and again. WARNING: The passwords generated using this option are not very random. If you use this option, make sure the attacker can not obtain a copy of the file. Also, note that the name of the file may be easily available from the ~/.history or ~/.bash_history file. -h, --help Print a help message. -r chars, --remove-chars=chars Don't use the specified characters in password. This option will disable the phomeme-based generator and uses the random password generator. -s, --secure Generate completely random, hard-to-memorize passwords. These should only be used for machine passwords, since otherwise it's almost guaranteed that users will simply write the password on a piece of paper taped to the monitor... -v, --no-vowels Generate random passwords that do not contain vowels or numbers that might be mistaken for vowels. It provides less secure passwords to allow system administrators to not have to worry with random passwords accidentally contain offensive substrings. -y, --symbols Include at least one special character in the password.
This version of pwgen was written by Theodore Ts'o