awk-gold-collection

commit 5b97c119a45afa7091d2c6d1146bf8d9a83ed3f6
parent 2a982636690c414943dd8dfb759787d78499f08c
Author: Luxferre <lux@ferre>
Date:   Tue, 12 Mar 2024 10:52:09 +0200

Added cardgen.awk

Diffstat:
M
README
 | 
2
++
A
utils/cardgen.awk
 | 
30
++++++++++++++++++++++++++++++

2 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/README b/README
@@ -32,5 +32,7 @@ Other AWK scripts have the usage described in their comment headers.
 * utils/textereo.awk: ASCII art stereogram generator
 * utils/tgl.awk: The Great Library of useful functions missing in POSIX AWK
 * utils/imeigen.awk: Random valid IMEI generator (with optional TAC prefix)
+* utils/cardgen.awk: Random valid banking card number generator
+  (with optional BIN prefix)
 
 --- Luxferre ---
diff --git a/utils/cardgen.awk b/utils/cardgen.awk
@@ -0,0 +1,30 @@
+# Valid banking card number generator script
+#
+# Usage: awk -f cardgen.awk [BIN]
+# you can pass any amount of digits, if less than 16 then the rest
+# is randomized and the checksum is calculated accordingly
+# if more, then it's truncated to 15 and the checksum is calculated 
+# if no BIN is passed, a fully random valid card number is generated
+#
+# Created by Luxferre in 2024, released into public domain
+
+# Luhn checksum (picoLuhn variation for 15 digits)
+function luhn(ccstr,  acc, i, l, d) {
+  acc = 0
+  l = length(ccstr) # must be odd in this variation
+  for(i=0;i<l;i++) {
+    d = int(substr(ccstr, i+1, 1)) # get current digit
+    acc = (acc + int(d * ((i%2) == 0 ? 2.2 : 1))) % 10 # accumulate
+  }
+  return (10 - acc) % 10 # finalize the check digit
+}
+
+BEGIN {
+  srand() # init PRNG
+  cc = ARGV[1]
+  gsub(/[^0-9]/, "", cc) # remove all non-digits
+  for(i=0;i<15;i++) # append 15 random digits
+    cc = cc int(rand()*10)
+  cc = substr(cc, 1, 15) # truncate to first 15 digits
+  print(cc luhn(cc)) # output complete number with checksum
+}