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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.
Don't copy trailing '=' or use head -c to limit to desired length.
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]
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.