[3427] Changes after review:

 - errors printed to stderr in dhcp4,dhcp6 main() function
 - path_replacer.sh is now better documented

src/bin/dhcp4/main.cc

@@ -138,6 +138,14 @@ main(int argc, char* argv[]) {
         LOG_INFO(dhcp4_logger, DHCP4_SHUTDOWN);
 
     } catch (const std::exception& ex) {
+
+        // First, we print the error on stderr (that should always work)
+        cerr << DHCP4_NAME << ": Fatal error during start up: " << ex.what()
+             << endl;
+
+        // Let's also try to log it using logging system, but we're not
+        // sure if it's usable (the exception may have been thrown from
+        // the logger subsystem)
         LOG_FATAL(dhcp4_logger, DHCP4_SERVER_FAILED).arg(ex.what());
         ret = EXIT_FAILURE;
     }

src/bin/dhcp6/main.cc

@@ -142,8 +142,15 @@ main(int argc, char* argv[]) {
         LOG_INFO(dhcp6_logger, DHCP6_SHUTDOWN);
 
     } catch (const std::exception& ex) {
+
+        // First, we print the error on stderr (that should always work)
+        cerr << DHCP6_NAME << "Fatal error during start up: " << ex.what()
+             << endl;
+
+        // Let's also try to log it using logging system, but we're not
+        // sure if it's usable (the exception may have been thrown from
+        // the logger subsystem)
         LOG_FATAL(dhcp6_logger, DHCP6_SERVER_FAILED).arg(ex.what());
-        cerr << "Fatal error during start up: " << ex.what() << endl;
         ret = EXIT_FAILURE;
     }
 

tools/path_replacer.sh.in

 #!/bin/sh
-
+# Copyright (C) 2014  Internet Systems Consortium, Inc. ("ISC")
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+# AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+# PERFORMANCE OF THIS SOFTWARE.
 #
-# This script replaces @prefix@ and @localstatedir@ variables with their
-# actual content. Usage:
+# This script replaces @prefix@, @localstatedir@ and other automake/autoconf
+# variables with their actual content.
+#
+# Invocation:
 #
 # ./path_replacer.sh input-file.in output-file
+#
+# This script is initially used to generate configuration files, but it is
+# generic and can be used to generate any text files.
+#
 
 prefix=@prefix@
 sysconfdir=@sysconfdir@
 localstatedir=@localstatedir@
 
+echo "Replacing \@prefix\@ with ${prefix}"
+echo "Replacing \@sysconfdir\@ with ${sysconfdir}"
 echo "Replacing \@localstatedir\@ with ${localstatedir}"
 
 echo "Input file: $1"