diff -r 000000000000 -r 6474c204b198 tools/trace-malloc/histogram-pretty.sh
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/trace-malloc/histogram-pretty.sh	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,63 @@
+#!/bin/sh
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#   histogram-pretty.sh [-c <count>] [-w <width>] <file>
+#
+# Pretty-print the histogram in file <file>, displaying at most
+# <count> rows.
+
+# How many rows are we gonna show?
+COUNT=20
+WIDTH=22
+
+# Read arguments
+while [ $# -gt 0 ]; do
+    case "$1" in
+    -c) COUNT=$2
+        shift 2
+        ;;
+    -w) WIDTH=$2
+        shift 2
+        ;;
+    *)  break
+        ;;
+    esac
+done
+
+FILE=$1
+
+# The first `awk' script computes a `TOTAL' row. Then, we sort by the
+# larges delta in bytes.
+awk '{ tobj += $2; tbytes += $3; } END { print "TOTAL", tobj, tbytes; }' ${FILE} > /tmp/$$.sorted
+
+sort -nr +2 ${FILE} >> /tmp/$$.sorted
+
+# Pretty-print, including percentages
+cat <<EOF > /tmp/$$.awk
+BEGIN {
+  printf "%-${WIDTH}s  Count    Bytes %Total   %Cov\n", "Type";
+  }
+\$1 == "TOTAL" {
+  tbytes = \$3;
+  }
+NR <= $COUNT {
+  if (\$1 != "TOTAL") {
+    covered += \$3;
+  }
+  printf "%-${WIDTH}s %6d %8d %6.2lf %6.2lf\n", \$1, \$2, \$3, 100.0 * \$3 / tbytes, 100.0 * covered / tbytes;
+  }
+NR > $COUNT {
+  oobjs += \$2;  obytes += \$3; covered += \$3;
+  }
+END {
+  printf "%-${WIDTH}s %6d %8d %6.2lf %6.2lf\n", "OTHER", oobjs, obytes, obytes * 100.0 / tbytes, covered * 100.0 / tbytes;
+  }
+EOF
+
+# Now pretty print the file, and spit it out on stdout.
+awk -f /tmp/$$.awk /tmp/$$.sorted
+
+rm -f /tmp/$$.awk /tmp/$$.sorted