Comments on: Generate Random Passwords on the Command Line http://dancingpenguinsoflight.com/2007/07/generate-random-passwords-on-command/ Thu, 09 Feb 2012 14:28:39 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Improved random password generator script | tail -f findings.out http://dancingpenguinsoflight.com/2007/07/generate-random-passwords-on-command/comment-page-1/#comment-23653 Improved random password generator script | tail -f findings.out Sun, 07 Nov 2010 15:33:07 +0000 http://dancingpenguinsoflight.com/2007/07/02/generate-random-passwords-on-the-command-line/#comment-23653 [...] have been using this script I wrote about a few years back to generate random passwords. It works, but it’s limited. [...] [...] have been using this script I wrote about a few years back to generate random passwords. It works, but it’s limited. [...]

]]> By: Simon http://dancingpenguinsoflight.com/2007/07/generate-random-passwords-on-command/comment-page-1/#comment-10 Simon Mon, 16 Jul 2007 08:46:00 +0000 http://dancingpenguinsoflight.com/2007/07/02/generate-random-passwords-on-the-command-line/#comment-10 The length limit is down to uuencode which produces output like :<br/>mgHZWDhtXSgIh6JR0Jh45Z0t/GRS2z52keGQIbT2NnpBGUF8IEcvEnczh/St<br/>yFCO3yxO2UbpZ39dwFoFRiIbskU6AXPkSskcB9fjYsqRhOVjxeo2CsOtkwtz<br/>qlOoXXd82BnuGsbgm4ho60lG1+7AZoU/DMJ3rilMTebYHw==<br/>====<br/>so when your take the next to last line you get some number of characters less than 60. My first though was that it might have been line breaks in the initial random string so switched to using 'dd'. <br/><br/>My script ended up like :<br/>echo `dd if=/dev/urandom bs=1k count=1 2>/dev/null | tr -dc '0-9a-zA-Z' | head -c ${pw_len}`<br/><br/>I simply took a fairly long input string, and deleted all the non-alphanumeric characters in it using 'tr'. The length limit is down to uuencode which produces output like :
mgHZWDhtXSgIh6JR0Jh45Z0t/GRS2z52keGQIbT2NnpBGUF8IEcvEnczh/St
yFCO3yxO2UbpZ39dwFoFRiIbskU6AXPkSskcB9fjYsqRhOVjxeo2CsOtkwtz
qlOoXXd82BnuGsbgm4ho60lG1+7AZoU/DMJ3rilMTebYHw==
====
so when your take the next to last line you get some number of characters less than 60. My first though was that it might have been line breaks in the initial random string so switched to using ‘dd’.

My script ended up like :
echo `dd if=/dev/urandom bs=1k count=1 2>/dev/null | tr -dc ’0-9a-zA-Z’ | head -c ${pw_len}`

I simply took a fairly long input string, and deleted all the non-alphanumeric characters in it using ‘tr’.

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