PWGEN - reference manual online

Generate pronounceable passwords.

October 2014
PWGEN(1)                             General Commands Manual                             PWGEN(1)

NAME pwgen - generate pronounceable passwords
SYNOPSIS pwgen [ OPTION ] [ pw_length ] [ num_pw ]
DESCRIPTION The pwgen program generates passwords which are designed to be easily memorized by humans, while being as secure as possible. Human-memorable passwords are never going to be as secure as completely completely 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 gen‐ erated 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 program. Used interactively, pwgen will display a screenful of passwords, allowing the user to pick a single password, and then quickly erase the screen. This pre‐ vents 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.
OPTIONS -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 compati‐ bility. -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 signifi‐ cantly, 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 recommended. -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 out‐ put is a tty device. -N, --num-passwords=num Generate num passwords. This defaults to a screenful if passwords are printed by columns, and one password otherwise. -n, --numerals Include at least one number in the password. This is the default 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 ~/ 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. -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 sim‐ ply 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 mis‐ taken for vowels. It provides less secure passwords to allow system administrators to not have to worry with random passwords accidentally contain offensive sub‐ strings. -y, --symbols Include at least one special character in the password.
AUTHOR This version of pwgen was written by Theodore Ts'o <>. It is modelled after a program originally written by Brandon S. Allbery, and then later extensively modi‐ fied by Olaf Titz, Jim Lynch, and others. It was rewritten from scratch by Theodore Ts'o because the original program was somewhat of a hack, and thus hard to maintain, and because the licensing status of the program was unclear.
SEE ALSO passwd(1)
pwgen version 2.07 October 2014 PWGEN(1)
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pwgen(1) referred by gpw(1) | pass(1)
refer to passwd(1)