Nice BASH Random Implementation

tags: bash dev fun random

05 Mar 2009 20:20

Today I wrote something like this in BASH:

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

This prints a random number from 0 to 3. How it works?

Firstly the command below prints one random byte using special Unix /dev/urandom device:

head -c 1 /dev/urandom

Piping this to | base64 gives us base64 representation of the byte.

Base64 is a method of encoding 8-bit data as human-readable strings using only 64 visible characters (letters, digits and some !@ and stuff). Whitespace is always ignored when reading base64 string. The standard is really nice, because you can for example read a base64-encoded file with a phone or send a printout of it with a classic mail. Because all the characters are human-readable, one can enter them and decode the original message. The format is used widely for sending emails.

It is important for us, that running base64 on a random byte gives us 2 bytes that are only "normal" characters, ie don't have any special meaning in any context (like some white characters may have).

Now comes the tricky part:

printf '%d' "'`head -c 1 /dev/urandom | base64`"

printf '%d' "'a" would give us 97 — this is the ASCII code of letter a. Remember we get two bytes of data after base64? No problem, printf cares in this case only about the first character.

As you may notice the output of this is one of these:

43
a number between 47 and 57
a number between 65 and 90
a number between 97 and 122

This gives us 64 possibilities. Great! 6 bits is just the same as 64.

This is when we get to BASH arithmetics. This is how it works:

echo $((7*12))

This should print 84 obviously. Knowing that enclosing a string in $( and ) causes BASH to run the enclosed command and return its results (just like using the backticks: `command`) this is everything.

The % means modulo in BASH arithmetic (just like in C, Java, Python, PHP, …), so this:

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64`")%4))

prints the number we generated (one of 43, 47…57, 65…90, 97…122) modulo 4. This needs to be 0, 1, 2 or 3.

Let's now check what the probability of receiving each of the digits.

Suppose /dev/urandom prints every possible byte with equal probability. We'll now analyze each byte (possibly) generated by /dev/urandom, it's base64 representation, ASCII code of first byte of the representation and the modulo 4 of it. We'll use a table for it:

1364

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1365

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1366

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1367

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1368

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1369

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 133) 1384

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1385

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1386

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1387

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1388

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1389

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 135) 1444

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1445

printf '%d' "'`head -c 1 /dev/urandom | base64`"

1446

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1447

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1448

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1449

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 141) 1484

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1485

echo $((7*12))

1486

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1487

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1488

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1489

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 145) 1504

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1505

echo $((7*12))

1506

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1507

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1508

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1509

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 147) 1524

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1525

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1526

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1527

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1528

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1529

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 149) 1544

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1545

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1546

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1547

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1548

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1549

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 151) 1604

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1605

printf '%d' "'`head -c 1 /dev/urandom | base64`"

1606

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1607

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1608

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1609

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 157) 1624

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1625

printf '%d' "'`head -c 1 /dev/urandom | base64`"

1626

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1627

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1628

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1629

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 159) 1684

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1685

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1686

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1687

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1688

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1689

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 165) 1704

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1705

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1706

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1707

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1708

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1709

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 167) 1764

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1765

printf '%d' "'`head -c 1 /dev/urandom | base64`"

1766

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1767

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1768

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1769

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 173) 1784

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1785

printf '%d' "'`head -c 1 /dev/urandom | base64`"

1786

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1787

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1788

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1789

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 175) 1844

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1845

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1846

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1847

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1848

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1849

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 181) 1864

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1865

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1866

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1867

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1868

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1869

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 183) 1884

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1885

head -c 1 /dev/urandom

1886

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1887

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1888

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1889

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 185) 1904

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1905

head -c 1 /dev/urandom

1906

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1907

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1908

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1909

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 187) 1924

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1925

printf '%d' "'`head -c 1 /dev/urandom | base64`"

1926

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1927

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1928

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1929

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 189) 1944

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1945

printf '%d' "'`head -c 1 /dev/urandom | base64`"

1946

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1947

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1948

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

1949

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 191) 2004

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2005

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2006

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2007

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2008

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2009

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 197) 2024

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2025

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2026

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2027

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2028

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2029

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 199) 2084

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2085

printf '%d' "'`head -c 1 /dev/urandom | base64`"

2086

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2087

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2088

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2089

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 205) 2104

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2105

printf '%d' "'`head -c 1 /dev/urandom | base64`"

2106

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2107

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2108

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2109

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 207) 2124

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2125

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2126

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2127

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2128

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2129

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 209) 2144

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2145

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2146

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2147

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2148

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2149

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 211) 2204

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2205

printf '%d' "'`head -c 1 /dev/urandom | base64`"

2206

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2207

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2208

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2209

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 217) 2224

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2225

printf '%d' "'`head -c 1 /dev/urandom | base64`"

2226

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2227

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2228

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2229

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 219) 2284

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2285

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2286

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2287

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2288

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2289

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 225) 2304

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2305

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2306

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2307

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2308

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2309

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 227) 2364

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2365

printf '%d' "'`head -c 1 /dev/urandom | base64`"

2366

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2367

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2368

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2369

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 233) 2384

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2385

printf '%d' "'`head -c 1 /dev/urandom | base64`"

2386

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2387

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2388

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2389

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 235) 2444

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2445

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2446

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2447

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2448

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2449

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 241) 2464

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2465

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2466

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2467

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2468

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2469

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 243) 2483 2484

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2485

head -c 1 /dev/urandom

2486

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2487

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2488

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2489

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 245) 2503 2504

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2505

head -c 1 /dev/urandom

2506

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2507

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2508

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2509

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 247) 2564

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2565

echo $((7*12))

2566

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2567

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2568

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2569

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 253) 2584

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2585

echo $((7*12))

2586

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2587

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2588

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

2589

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

(code 255)

/dev/urandom byte	base64	code of the first letter of base64	the same modulo 4
(code 0)	AA==	65	1
(code 1)	AQ==	65	1
(code 2)	Ag==	65	1
(code 3)	Aw==	65	1
(code 4)	BA==	66	2
(code 5)	BQ==	66	2
(code 6)	Bg==	66	2
(code 7)	Bw==	66	2
(code 8)	CA==	67	3
(code 9)	CQ==	67	3
(code 10)	Cg==	67	3
(code 11)	Cw==	67	3
(code 12)	DA==	68	0
(code 13)	DQ==	68	0
(␌⎺␍␊ 14)	Dg==	68	0
(code 15)	Dw==	68	0
(code 16)	EA==	69	1
(code 17)	EQ==	69	1
(code 18)	Eg==	69	1
(code 19)	Ew==	69	1
(code 20)	FA==	70	2
(code 21)	FQ==	70	2
(code 22)	Fg==	70	2
(code 23)	Fw==	70	2
(code 24)	GA==	71	3
(code 25)	GQ==	71	3
(code 26)	Gg==	71	3
(code 27)	Gw==	71	3
(code 28)	HA==	72	0
(code 29)	HQ==	72	0
(code 30)	Hg==	72	0
(code 31)	Hw==	72	0
(code 32)	IA==	73	1
! (code 33)	IQ==	73	1
" (code 34)	Ig==	73	1
# (code 35)	Iw==	73	1
$ (code 36)	JA==	74	2
% (code 37)	JQ==	74	2
& (code 38)	Jg==	74	2
' (code 39)	Jw==	74	2
( (code 40)	KA==	75	3
) (code 41)	KQ==	75	3
* (code 42)	Kg==	75	3
+ (code 43)	Kw==	75	3
, (code 44)	LA==	76	0
- (code 45)	LQ==	76	0
. (code 46)	Lg==	76	0
/ (code 47)	Lw==	76	0
0 (code 48)	MA==	77	1
1 (code 49)	MQ==	77	1
2 (code 50)	Mg==	77	1
3 (code 51)	Mw==	77	1
4 (code 52)	NA==	78	2
5 (code 53)	NQ==	78	2
6 (code 54)	Ng==	78	2
7 (code 55)	Nw==	78	2
8 (code 56)	OA==	79	3
9 (code 57)	OQ==	79	3
: (code 58)	Og==	79	3
; (code 59)	Ow==	79	3
< (code 60)	PA==	80	0
= (code 61)	PQ==	80	0
> (code 62)	Pg==	80	0
? (code 63)	Pw==	80	0
@ (code 64)	QA==	81	1
A (code 65)	QQ==	81	1
B (code 66)	Qg==	81	1
C (code 67)	Qw==	81	1
D (code 68)	RA==	82	2
E (code 69)	RQ==	82	2
F (code 70)	Rg==	82	2
G (code 71)	Rw==	82	2
H (code 72)	SA==	83	3
I (code 73)	SQ==	83	3
J (code 74)	Sg==	83	3
K (code 75)	Sw==	83	3
L (code 76)	TA==	84	0
M (code 77)	TQ==	84	0
N (code 78)	Tg==	84	0
O (code 79)	Tw==	84	0
P (code 80)	UA==	85	1
Q (code 81)	UQ==	85	1
R (code 82)	Ug==	85	1
S (code 83)	Uw==	85	1
T (code 84)	VA==	86	2
U (code 85)	VQ==	86	2
V (code 86)	Vg==	86	2
W (code 87)	Vw==	86	2
X (code 88)	WA==	87	3
Y (code 89)	WQ==	87	3
Z (code 90)	Wg==	87	3
[ (code 91)	Ww==	87	3
\ (code 92)	XA==	88	0
] (code 93)	XQ==	88	0
^ (code 94)	Xg==	88	0
_ (code 95)	Xw==	88	0
` (code 96)	YA==	89	1
a (code 97)	YQ==	89	1
b (code 98)	Yg==	89	1
c (code 99)	Yw==	89	1
d (code 100)	ZA==	90	2
e (code 101)	ZQ==	90	2
f (code 102)	Zg==	90	2
g (code 103)	Zw==	90	2
h (code 104)	aA==	97	1
i (code 105)	aQ==	97	1
j (code 106)	ag==	97	1
k (code 107)	aw==	97	1
l (code 108)	bA==	98	2
m (code 109)	bQ==	98	2
n (code 110)	bg==	98	2
o (code 111)	bw==	98	2
p (code 112)	cA==	99	3
q (code 113)	cQ==	99	3
r (code 114)	cg==	99	3
s (code 115)	cw==	99	3
t (code 116)	dA==	100	0
u (code 117)	dQ==	100	0
v (code 118)	dg==	100	0
w (code 119)	dw==	100	0
x (code 120)	eA==	101	1
y (code 121)	eQ==	101	1
z (code 122)	eg==	101	1
{ (code 123)	ew==	101	1
\| (code 124)	fA==	102	2
} (code 125)	fQ==	102	2
~ (code 126)	fg==	102	2
(code 127)	fw==	102	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1320 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1321 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1322 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1323	1324 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1325 `echo $((7*12))` 1326 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1327 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1328 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1329 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 129)	gQ==	103	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1340 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1341 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1342 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1343	1344 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1345 `echo $((7*12))` 1346 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1347 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1348 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1349 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 131)	gw==	103	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1360 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1361 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1362 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1363	hQ==	104	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1380 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1381 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1382 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1383	hw==	104	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1400 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1401 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1402 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1403	1404 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1405 `head -c 1 /dev/urandom` 1406 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1407 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1408 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1409 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 137)	iQ==	105	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1420 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1421 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1422 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1423	1424 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1425 `head -c 1 /dev/urandom` 1426 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1427 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1428 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1429 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 139)	iw==	105	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1440 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1441 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1442 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1443	jQ==	106	2
(code 142)	jg==	106	2
(code 143)	jw==	106	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1480 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1481 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1482 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1483
kQ==	107	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1500 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1501 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1502 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1503
kw==	107	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1520 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1521 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1522 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1523
lQ==	108	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1540 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1541 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1542 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1543
lw==	108	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1560 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1561 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1562 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1563	1564 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1565 `head -c 1 /dev/urandom` 1566 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1567 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1568 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1569 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 153)	mQ==	109	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1580 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1581 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1582 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1583	1584 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1585 `head -c 1 /dev/urandom` 1586 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1587 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1588 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1589 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 155)	mw==	109	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1600 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1601 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1602 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1603	nQ==	110	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1620 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1621 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1622 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1623	nw==	110	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1640 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1641 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1642 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1643	1644 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1645 `echo $((7*12))` 1646 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1647 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1648 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1649 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 161)	oQ==	111	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1660 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1661 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1662 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1663	1664 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1665 `echo $((7*12))` 1666 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1667 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1668 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1669 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 163)	ow==	111	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1680 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1681 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1682 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1683	pQ==	112	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1700 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1701 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1702 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1703	pw==	112	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1720 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1721 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1722 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1723	1724 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1725 `head -c 1 /dev/urandom` 1726 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1727 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1728 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1729 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 169)	qQ==	113	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1740 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1741 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1742 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1743	1744 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1745 `head -c 1 /dev/urandom` 1746 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1747 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1748 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1749 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 171)	qw==	113	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1760 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1761 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1762 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1763	rQ==	114	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1780 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1781 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1782 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1783	rw==	114	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1800 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1801 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1802 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1803	1804 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1805 `echo $((7*12))` 1806 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1807 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1808 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1809 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 177)	sQ==	115	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1820 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1821 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1822 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1823	1824 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1825 `echo $((7*12))` 1826 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1827 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1828 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1829 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 179)	sw==	115	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1840 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1841 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1842 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1843	tQ==	116	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1860 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1861 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1862 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1863	tw==	116	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1880 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1881 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1882 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1883
uQ==	117	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1900 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1901 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1902 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1903
uw==	117	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1920 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1921 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1922 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1923
vQ==	118	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1940 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1941 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1942 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1943
vw==	118	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1960 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1961 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1962 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1963	1964 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1965 `echo $((7*12))` 1966 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1967 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1968 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1969 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 193)	wQ==	119	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1980 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1981 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1982 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1983	1984 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1985 `echo $((7*12))` 1986 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1987 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1988 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 1989 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 195)	ww==	119	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2000 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2001 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2002 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2003	xQ==	120	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2020 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2021 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2022 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2023	xw==	120	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2040 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2041 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2042 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2043	2044 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2045 `head -c 1 /dev/urandom` 2046 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2047 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2048 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2049 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 201)	yQ==	121	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2060 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2061 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2062 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2063	2064 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2065 `head -c 1 /dev/urandom` 2066 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2067 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2068 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2069 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 203)	yw==	121	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2080 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2081 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2082 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2083	zQ==	122	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2100 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2101 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2102 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2103	zw==	122	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2120 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2121 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2122 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2123
0Q==	48	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2140 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2141 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2142 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2143
0w==	48	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2160 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2161 `head -c 1 /dev/urandom` 2162 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2163	2164 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2165 `head -c 1 /dev/urandom` 2166 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2167 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2168 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2169 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 213)	1Q==	49	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2180 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2181 `head -c 1 /dev/urandom` 2182 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2183	2184 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2185 `head -c 1 /dev/urandom` 2186 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2187 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2188 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2189 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 215)	1w==	49	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2200 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2201 printf '%d' "'`head -c 1 /dev/urandom \| base64`" 2202 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2203	2Q==	50	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2220 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2221 printf '%d' "'`head -c 1 /dev/urandom \| base64`" 2222 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2223	2w==	50	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2240 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2241 `echo $((7*12))` 2242 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2243	2244 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2245 `echo $((7*12))` 2246 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2247 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2248 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2249 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 221)	3Q==	51	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2260 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2261 `echo $((7*12))` 2262 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2263	2264 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2265 `echo $((7*12))` 2266 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2267 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2268 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2269 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 223)	3w==	51	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2280 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2281 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64`")%4)) 2282 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2283	4Q==	52	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2300 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2301 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64`")%4)) 2302 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2303	4w==	52	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2320 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2321 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2322 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2323	2324 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2325 `head -c 1 /dev/urandom` 2326 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2327 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2328 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2329 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 229)	5Q==	53	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2340 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2341 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2342 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2343	2344 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2345 `head -c 1 /dev/urandom` 2346 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2347 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2348 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2349 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 231)	5w==	53	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2360 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2361 #!/bin/bash function random() { echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) } ret=`i=0; time while [ $i -lt 100 ]; do random ; i=$((i+1)); done` echo -n '0: ' ; echo "$ret" \| grep 0 \| wc -l echo -n '1: ' ; echo "$ret" \| grep 1 \| wc -l echo -n '2: ' ; echo "$ret" \| grep 2 \| wc -l echo -n '3: ' ; echo "$ret" \| grep 3 \| wc -l 2362 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2363	6Q==	54	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2380 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2381 #!/bin/bash function random() { echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) } ret=`i=0; time while [ $i -lt 100 ]; do random ; i=$((i+1)); done` echo -n '0: ' ; echo "$ret" \| grep 0 \| wc -l echo -n '1: ' ; echo "$ret" \| grep 1 \| wc -l echo -n '2: ' ; echo "$ret" \| grep 2 \| wc -l echo -n '3: ' ; echo "$ret" \| grep 3 \| wc -l 2382 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2383	6w==	54	2
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2400 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2401Nice BASH Random Implementation2402 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2403	2404 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2405 `echo $((7*12))` 2406 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2407 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2408 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2409 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 237)	7Q==	55	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2420 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2421Nice BASH Random Implementation2422 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2423	2424 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2425 `echo $((7*12))` 2426 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2427 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2428 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2429 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 239)	7w==	55	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2440 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2441Comments: 62442 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2443	8Q==	56	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2460 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2461Comments: 62462 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2463	8w==	56	0
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2480 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2481 2482 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4))
9Q==	57	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2500 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2501 2502 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4))
9w==	57	1
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2520 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2521 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2522 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2523	2524 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2525 `echo $((7*12))` 2526 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2527 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2528 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2529 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 249)	+Q==	43	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2540 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2541 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2542 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2543	2544 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2545 `echo $((7*12))` 2546 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2547 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2548 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2549 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) (code 251)	+w==	43	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2560 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2561 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2562 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2563
/Q==	47	3
echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2580 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2581 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2582 echo $(($(printf '%d' "'`head -c 1 /dev/urandom \| base64 \| tr A D`")%4)) 2583
/w==	47	3

(Some of the symbols in the first column may appear not visible or otherwise look strange. This is normal, there are many characters in ASCII that has (or had) some special meaning.)

Let's count have many 0s, 1s, 2s and 3s did we get:

0	60
1	68
2	64
3	64

This is not ideal, because you get statistically slightly more 1s than 0s, but if you don't care too much, this is all!

If you care however, here is some solution. We need to get 4 results that give us 1 and convert them to some that gives 0:

echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))

Notice the tr A D. This changes each A to D in the base64 output. Thus four rows of table above (for 0 to 4 codes) should behave like the 12 to 15 codes, thus giving 0 at the end instead of 1.

We're done. Let's enclose the procedure in function clause and create a sample code that tells us how many 0s, 1s, 2s and 3s where hit within 100 shots.

#!/bin/bash

function random() {
    echo $(($(printf '%d' "'`head -c 1 /dev/urandom | base64 | tr A D`")%4))
}

ret=`i=0; time while [ $i -lt 100 ]; do random ; i=$((i+1)); done`

echo -n '0: ' ; echo "$ret" | grep 0 | wc -l
echo -n '1: ' ; echo "$ret" | grep 1 | wc -l
echo -n '2: ' ; echo "$ret" | grep 2 | wc -l
echo -n '3: ' ; echo "$ret" | grep 3 | wc -l

The program also shows how much time did it take to generate the numbers. Adjust the 100 to your needs ;).

UPDATE: having this article posted on reddit programming gave me actually much much better ways of doing a random function (see in comments). Thank you for your replies!

Comments: 6

Po Devcampie

tags: bash blog devcamp facebook opiwo polish

26 Oct 2008 15:59

Zdecydowałem, że mój blog musi być bardziej pozytywny.

Zatem, po pierwsze: iPhone rządzi, bo ma basha.

Po drugie: devcamp rządził :]. Chłopaki z www.socjum.pl też są spoko i zapraszają do Krakowa na imprezę, jaką długo spamiętamy.

Po trzecie: z pomocą Zająca odpaliłem na moim lapie Compiza w konfiguracji Dual Head na karcie graficznej Intela (a jak wszyscy wiedzą mam dwie karty graficzne, w moim kompie).

Niedługo będzie o pisaniu aplikacji do facebooka. A teraz sobie wymyślam jak powinien wyglądać serwis opiwo.com (czy raczej jak działać), żeby każdego chwycił za serce i spowodował efekt ŁAŁ.

Szczegóły wkrótce.

PS: Jeszcze chciałem przeprosić, że przynudzałem tak długo o tym JSON-RPC. Jak ktoś chętny: oto prezentacja.

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Piotr Gabryjeluk

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Nice BASH Random Implementation

2482

2502

Comments: 6

Po Devcampie

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