curl-trace

#!/bin/sh

curl --no-progress-meter -o /dev/null --trace - "$@" | (
  set -- awk
  type gawk >/dev/null 2>&1 && set -- gawk -n
  LC_ALL=C "$@" '
    BEGIN {
      printed_header = 0
      printed_data = 0
      output_stdout = 0
    }

    /^[0-9a-f]+:/ {
      $0 = substr($0, 7, 47)
      for (i = 1; i <= NF; i++) {
        line = sprintf("%c", int("0x" (last = $i)))
        if (output_stdout) {
          printf "%s", line
        } else {
          printf "%s", line > "/dev/stderr"
        }
      }
    }

    /^<= Recv header/ {
      if (!printed_header) {
        line = "========================================"
        if (output_stdout) {
          print line
        } else {
          print line > "/dev/stderr"
        }
        printed_header = 1
      }
    } 

    /^== Info: .* sent off/ {
      if (last != "0a") {
        if (output_stdout) {
          print ""
        } else {
          print "" > "/dev/stderr"
        }
      }
      line = "========================================"
      if (output_stdout) {
        print line
      } else {
        print line > "/dev/stderr"
      }
    }

    /^<= Recv data/ { 
      if (!printed_data) {
        line = "========================================"
        if (output_stdout) {
          print line
        } else {
          print line > "/dev/stderr"
        }
        printed_data = 1
      }
      output_stdout = 1

    END {
      print ""
    }
  '
)