"track" is a script I've used for ages to track the progress of a build.

Unlike whereintheworld, it continuously monitors the log file; it also
produses less verbose output.

tools/tools/README

@@ -53,6 +53,7 @@ scsi-defects	Get at the primary or grown defect list of a SCSI disk.
 sysdoc		Build a manual page with available sysctls for a specific
 		kernel configuration.
 tinybsd		Script to build FreeBSD embedded systems.
+track		Track the progress of a world / kernel build
 vop_table	Generates a HTML document that shows all the VOP's in
 		the kernel.
 whereintheworld	Summarizes "make world" output.

tools/tools/track/Makefile

@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+PREFIX?=	/usr/local
+BINDIR?=	${PREFIX}/bin
+SCRIPTS=	track.sh
+
+.include <bsd.prog.mk>

tools/tools/track/track.sh

@@ -0,0 +1,49 @@
+#!/bin/sh
+#-
+# Copyright (c) 2008 Dag-Erling Coïdan Smørgrav
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer
+#    in this position and unchanged.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# $FreeBSD$
+#
+
+tail -10000 -F "$@" |
+while read line
+do
+	case $line in
+	\>\>\>*)
+		endl="\r\n"
+		;;
+	\*\*\*\ Error*)
+		endl="\r\n"
+		;;
+	\=\=\=*)
+		endl="\r"
+		;;
+	*)
+		continue
+		;;
+	esac
+	printf "%s%*s${endl}" "${line}" $((${COLUMNS:-80} - ${#line} - 1)) " "
+done