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 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 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 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.
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 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 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 output 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 ~/your_favorite.mp3
#your@email.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.
AUTHOR
This version of pwgen was written by Theodore Ts'o
<tytso@alum.mit.edu>. It is modelled after a program
originally written by Brandon S. Allbery, and then later
extensively modified 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 2.08 August 2017 PWGEN(1)
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