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Generate an XKCD #936 style 4 word password

Terminal - Generate an XKCD #936 style 4 word password
cat /usr/share/dict/words | grep -P ^[a-z].* | grep -v "'s$" | grep -Pv ^.\{1,15\}$ | shuf -n4 | tr '\n' ' ' | sed 's/$/\n/'
2011-08-15 01:03:48
User: bugmenot
Functions: cat grep sed tr
-2
Up
Down
Generate an XKCD #936 style 4 word password

The first grep rejects capitalised words since the dict has proper nouns in it that you mightn't want to use. The second grep rejects words with ending in apostrophe s, and the third forces the words to be at least 15 characters long.

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Alternatives

There are 4 alternatives - vote for the best!

Terminal - Alternatives
shuf -n4 /usr/share/dict/words | tr -d '\n'
2011-08-10 13:04:39
User: Strawp
Functions: tr
Tags: tr xkcd shuf
19
Up
Down
Generate an XKCD #936 style 4 word password

4 random words are better than one obfuscated word

http://xkcd.com/936/

Show sample output | Comments (9) | Add to favourites | Report as malicious
shuf -n4 /usr/share/dict/words | sed -e ':a;N;$!ba;s/\n/ /g;s/'\''//g;s/\b\(.\)/\u\1/g;s/ //g'
2011-08-11 19:49:21
User: vasti
Functions: sed
Tags: sed regex xkcd shuf
1
Up
Down
Alternative way to generate an XKCD #936 style 4 word password usig sed

This is what I came up to generate XKCD #936 style four-word password.

Since first letter of every word is capitalized it looks a bit more readable to my eyes.

Also strips single quotes.

And yes - regex is a bit of a kludge, but that's the bes i could think of.

Show sample output | Comments (0) | Add to favourites | Report as malicious
jot 4 | awk '{ print "wc -l /usr/share/dict/words | awk '"'"'{ print \"echo $[ $RANDOM * $RANDOM % \" $1 \"]\" }'"'"' | bash | awk '"'"'{ print \"sed -n \" $1 \"p /usr/share/dict/words\" }'"'"' | bash" }' | bash | tr -d '\n' | sed 's/$/\n/'
2011-08-16 00:26:56
User: fathwad
Functions: awk bash sed tr
Tags: tr xkcd
0
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Down
Generate an XKCD #936 style 4 word password

So I use OSX and don't have the shuf command. This is what I could come up with.

This command assumes /usr/share/dict/words does not surpass 137,817,948 lines and line selection is NOT uniformly random.

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echo $(grep "^[^']\{3,5\}$" /usr/share/dict/words|shuf -n4)
2011-08-23 21:15:18
User: j_melis
Functions: echo grep
Tags: awk xkcd
0
Up
Down
Generate an XKCD #936 style 4 word password

The improvement of this command over Strawp's original alternative is that you can specify the size of the words, in this particular case words between 3 and 5 character's long. It also excludes words that contain apostrophes, if you'd rather keep those words simply substitue [^'] for .

Show sample output | Comments (3) | Add to favourites | Report as malicious
shuf /usr/share/dict/words |grep "^[^']\{3,5\}$" |head -n4
2011-08-24 03:43:55
User: menachem
Functions: grep head
Tags: awk xkcd
0
Up
Down
Generate an XKCD #936 style 4 word password

This does the same thing that the command 'j_melis' submitted, but does it a lot quicker.

That command takes 43 seconds to complete on my system, while the command I submitted takes 6 seconds.

Show sample output | Comments (0) | Add to favourites | Report as malicious

Know a better way?

If you can do better, submit your command here.

What others think

You almost never need cat and grep in the same command.

Comment by dbbolton 92 weeks and 5 days ago
grep '[a-z]\{15,\}' /usr/share/dict/words
Comment by putnamhill 92 weeks and 5 days ago

I love the commands where cat(1) is piped into grep(1). Gives me a warm fuzzy feeling inside. :)

Comment by atoponce 92 weeks and 1 day ago

Your point of view

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