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Find random strings within /dev/urandom. Using grep filter to just Alphanumeric characters, and then print the first 30 and remove all the line feeds.
-B flag = don't include characters that can be confused for other characters (this helps when you give someone their password for the first time so they don't cause a lockout with, for example, denyhosts or fail2ban)
-s flag = make a "secure", or hard-to-crack password
-y flag = include special characters (not used in the example because so many people hate it -- however I recommend it)
"1 10" = output 1 password, make it 10 characters in length
For even more secure passwords please use the -y flag to include special characters like so:
pwgen -Bsy 10 1
If you want a password length longer than 6, changing the -c6 to read -c8 will give you 8 random characters instead of 6. To end up with a line-feed, use this with echo:
# echo `< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c6`
According to the gpg(1) manual:
--gen-random 0|1|2 count
Emit count random bytes of the given quality level 0, 1 or 2. If count is not given or zero, an endless sequence of random bytes will be emitted. If used with --armor the output will be base64 encoded. PLEASE, don't use this command unless you know what you are doing; it may remove precious entropy from the system!
If your entropy pool is critical for various operations on your system, then using this command is not recommended to generate a secure password. With that said, regenerating entropy is as simple as:
du -s /
This is a quick way to generate a strong, base64 encoded, secure password of arbitrary length, using your entropy pool (example above shows a 30-character long password).
See: "man pwgen" for full details.
Some Linux distros may not have pwgen included in the base distribution
so you maye have to install it (eg in Mandriva Linux: "urpmi pwgen").
for Mac OS X
Generates a random 8-character password that can be typed using only the left hand on a QWERTY keyboard. Useful to avoid taking your hand off of the mouse, especially if your username is left-handed. Change the 8 to your length of choice, add or remove characters from the list based on your preferences or kezboard layout, etc.
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. [from pwgen man page]
Don't copy trailing '=' or use head -c to limit to desired length.
These are my favourite switches on pwgen:
-B Don't include ambiguous characters in the password
-n Include at least one number in the password
-y Include at least one special symbol in the password
-c Include at least one capital letter in the password
It just works!
Add a number to set password length, add another to set how many password to output. Example:
pwgen -Bnyc 12 20
this will output 20 password of 12 chars length.
This is just a proof of concept: A FILE WHICH CAN AUTOMOUNT ITSELF through a SIMPLY ENCODED script. It takes advantage of the OFFSET option of mount, and uses it as a password (see that 9191? just change it to something similar, around 9k). It works fine, mounts, gets modified, updated, and can be moved by just copying it.
USAGE: SEE SAMPLE OUTPUT
The file is composed of three parts:
a) The legible script (about 242 bytes)
b) A random text fill to reach the OFFSET size (equals PASSWORD minus 242)
c) The actual filesystem
Logically, (a)+(b) = PASSWORD, that means OFFSET, and mount uses that option.
PLEASE NOTE: THIS IS NOT AN ENCRYPTED FILESYSTEM. To improve it, it can be mounted with a better encryption script and used with encfs or cryptfs. The idea was just to test the concept... with one line :)
It applies the original idea of http://www.commandlinefu.com/commands/view/7382/command-for-john-cons for encrypting the file.
The embedded bash script can be grown, of course, and the offset recalculation goes fine. I have my own version with bash --init-file to startup a bashrc with a well-defined environment, aliases, variables.
Generates password consisting of alphanumeric characters, defaults to 16 characters unless argument given.
Another password maker, for human-unfriendly passwords. '-base64' output will make sure it it can be typed on a keyboard, though the output string length will always be a multiple of 4.
This was useful to generate random passwords to some webpage users, using the sample code, inside a bash script
make password randomly, default 8 chars, using bash3.X only, no external program.
Of course you will have to install Digest::SHA and perl before this will work :)
Maximum length is 43 for SHA256. If you need more, use SHA512 or the hexadecimal form: sha256_hex()
Use the excellent sensiblepasswords.com to a generate random (yet easy-to-remember) password every second, and copy it to the clipboard. Useful for generating a list of passwords and pasting them into a spreadsheet.
This script uses "madebynathan"'s "cb" function (http://madebynathan.com/2011/10/04/a-nicer-way-to-use-xclip/); you could also replace "cb" with
xclip -selection c
Remove "while true; do" and "; done" to generate and copy only 1 password.
Generate a table of random 10 character passwords
generate a table with 10 character ambiguous random passwords which include at least one special character in in password
I know there are a lot of random password generators out there, but I wanted something that put out something besides hex. Set count equal to the number of bytes you want.