Awk program: addhex

• Hex numbers are can be prefixed with 0x, or $, or not prefixed at all.
• Example hex strings include $DeadBeef, 0x4E71, -ee7b, and 000069FF.
• Multiple numbers can be on each line.
• Other text is usually ignored properly.
• Numbers can be up to +/- 2^48, or 16^12, or $FFFFFFFFFFFF in size.
• The sum of the numbers must also be less than 2^48.
• Usage: addhex file

#!/usr/bin/env -S awk -f
# addhex - adds hex numbers.
# addhex is Copyright Daniel K. Allen, 2023-2025.
# All rights reserved.
#
# 12 Jul 2023 - Created by Dan Allen.
# 13 Jul 2023 - Uses hex2decimal(), and supports many numbers per line.
# 17 Sep 2025 - Supports negative numbers as well.
#

BEGIN {
  sum = n = 0
  a["0"] = 0; a["1"] = 1; a["2"] = 2; a["3"] = 3; a["4"] = 4; a["5"] = 5
  a["6"] = 6; a["7"] = 7; a["8"] = 8; a["9"] = 9; a["A"] = 10; a["B"] = 11
  a["C"] = 12; a["D"] = 13; a["E"] = 14; a["F"] = 15; a["a"] = 10
  a["b"] = 11; a["c"] = 12; a["d"] = 13; a["e"] = 14; a["f"] = 15   
}

{
  for (i = 1; i <= NF; i++) {
    sub(/^\$/,"",$i) # remove leading dollar signs
    sub(/^0x/,"",$i) # remove leading hex indicator
    if ($i !~ /^[-0-9A-Fa-f]+$/) next # skip non-hex lines
    x = hex2decimal($i)
    printf("%8s --> %10d\n",$i,x)
    sum += x
    n++
  }
}

END {
  if (n > 0)
    printf("%08x --> %10d SUM   %.2f AVG   %d N\n",sum,sum,sum/n,n)
}

function hex2decimal(x,  d,i,n,v,s) # hex string to decimal integer
{
  d = 0
  s = 1
  if (substr(x,1,1) == "-") {
    s = -1
    x = substr(x,2)
  }
  n = length(x)
  for (i = 0; i < n; i++) {
    v = a[substr(x,n-i,1)]
    d += v * 16^i
  }
  return s*d 
}