diff --git a/scripts/tools/fg-check b/scripts/tools/fg-check
new file mode 100755
index 000000000..101f66da9
--- /dev/null
+++ b/scripts/tools/fg-check
@@ -0,0 +1,95 @@
+#!/bin/bash
+#
+# Checks source code and data for potential problems.
+# Meant to be executed before submitting/committing.
+
+
+SELF=${0/#*\/}
+
+# optional apps
+RLE=$(which rle &>/dev/null)              # http://members.aon.at/mfranz/rle.tar.gz (depends on Qt lib)
+AC3D_SCAN=$(which ac3d-scan 2>/dev/null)  # http://members.aon.at/mfranz/ac3d-scan
+
+
+function ERROR  { echo -e "\e[31;1m$*\e[m";   }
+function LOG    { echo -e "\e[35m$*\e[m";     }
+function RESULT { echo -e "\t$*";             }
+
+
+TMP=$(mktemp -d -t $SELF.XXX) || (echo "$0: can't create temporary dir"; exit 1)
+trap "rm -rf $TMP" 0 1 2 3 13 15
+
+
+LOG "checking for spaces in filenames ..."
+find .|grep " "|while read i; do RESULT "$i"; done
+
+
+LOG "checking for upper-case extensions ..."       # except *.TXT
+find .|while read i; do
+	case "$i" in .|..|CVS/*|*/CVS/*|*.Opt|*.README|*.Po) continue ;; esac
+	base=${i/#.*\/}
+	ext=${base/#*./}
+	[ "$base" == "$ext" ] && continue          # has no extension
+	ext=$(echo $ext|sed -e 's,[^A-Za-z],,'g)
+	[ -z "$ext" ] && continue                  # only non-letters
+	lcext=$(echo $ext|sed -e 's,\(.*\),\L\1,')
+	[ "$ext" != "$lcext" -a "$lcext" != "txt" ] && RESULT "$i"
+done
+
+
+LOG "checking for DOS line endings ..."
+find . -type f|while read i; do
+	desc=$(file -b "$i")
+	case "$desc" in *text*)
+		grep "
$" "$i" >/dev/null && RESULT "$i"
+		;;
+	esac
+done
+
+
+LOG "checking for uncompressed textures ..."
+find . -iname \*.rgb -o -iname \*.rgba|while read i; do
+	if file "$i"|grep -v RLE >/dev/null; then
+		new=$TMP/sgi.rgb
+		convert "$i" -compress RLE sgi:$new
+		[ "$RLE" ] && $RLE $new 2>/dev/null
+		perl -e '
+			my $file = shift;
+			my $old = -s $file;
+			my $new = -s shift;
+			if ($new < $old) {
+				printf "\t$file:  could be %0.02f%% of current size (%d bytes less)\n",
+						100 * $new / $old, $old - $new;
+			}
+		' "$i" $new
+	fi
+done
+
+
+if [ "$AC3D_SCAN" ]; then
+	LOG "checking for AC3D sanity ..."
+	find . -iname \*.ac|while read i; do
+		case "$i" in configure.ac|*/configure.ac) continue ;; esac
+		result=$($AC3D_SCAN <$i 2>&1)
+		[ "$result" ] && echo -e "$result\n\t... in file \e[36m$i\e[m";
+	done
+fi
+
+
+LOG "checking for XML syntax ..."
+find . -name \*.xml|while read i; do
+	xmllint $i >/dev/null || RESULT "... min file \e[36m$i\e[m"
+done
+
+
+LOG "checking for 'if (foo) delete foo;' ..."
+find . -iregex ".*\.\([ch]\(xx\|pp\)\|cc\|h\)$"|while read i; do perl -e '
+	my $i = 0;
+	my $name = $ARGV[0];
+	undef $/;
+	$_ = <>;
+	s/(if\s*\(([^\)]+)\)\s*delete(?:\s+|\s*\[\]\s*)\2\s*;)/print "$1\n" and $i++/ges;
+	print "\t... \033[36min file $name\033[m\n" if $i;
+' "$i"; done
+
+
diff --git a/scripts/tools/fg-submit b/scripts/tools/fg-submit
index f113f6b6d..af740a23e 100755
--- a/scripts/tools/fg-submit
+++ b/scripts/tools/fg-submit
@@ -11,39 +11,44 @@
 #         $ fg-submit      # generates foo.tar.bz2 and foo.diff
 #
 # The archive contains a copy of the diff, so the extra diff file
-# shouldn't be sumitted. It's only left for convenience.
+# shouldn't be submitted. It's only left for (in?)convenience.
 
-SELF=$(basename $0)
-AIRCRAFT=$(basename $PWD)
+SELF=${0/#*\/}
+AIRCRAFT=${PWD/#*\/}
 
 CVS=/usr/bin/cvs
 ARCHIVE=$AIRCRAFT.tar.bz2
 DIFF=$AIRCRAFT.diff
+CDIFF=$DIFF.bz2
 
 
-function ERROR  { echo -e "\e[31;1m$*\e[m";   }
-function LOG    { echo -e "\e[35m$*\e[m";     }
-function ADD    { echo -e "\e[32m\t+ $*\e[m"; }
-function REJECT { echo -e "\e[31m\t- $*\e[m"; }
+function ERROR   { echo -e "\e[31;1m$*\e[m";   }
+function LOG     { echo -e "\e[35m$*\e[m";     }
+function NEW     { echo -e "\e[32m\t+ $*\e[m"; }
+function CHANGED { echo -e "\e[36m\t+ $*\e[m"; }
+function REJECT  { echo -e "\e[31m\t- $*\e[m"; }
 
 function diffstat {
 	# output diff statistics, similar to the "diffstat" utility
 	awk '
+		function line(a, r, c, f) {
+			print "\t\033[32m"a"\033[m\t\033[31m"r"\033[m\t\033[34m"c"\033[m\t"f
+		}
 		function dofile() {
 			if (!file) {
-				return;
+				return
 			}
 			if (bin) {
-				print "\t\tbinary\t\t"file;
+				line("\033[m. . . .", "\033[mbinary", "\033[m. . . .", file)
 			} else {
-				print "\t+"a"\t-"r"\t!"c"\t"file
+				line(a, r, c, file)
 				at += a; rt += r; ct += c;
 			}
-			a = r = c = 0;
+			a = r = c = 0
 		}
 		BEGIN      {
-			print "\tadded___removed_changed___________________________________";
-			a = r = c = at = rt = ct = n = bin = 0;
+			print "\tadded---removed-changed----------------------------------------"
+			a = r = c = at = rt = ct = n = bin = 0
 		}
 		/^Index: / { dofile(); scan = bin = 0; file = $2; n += 1; next }
 		/^@@/      { scan = 1; next }
@@ -52,11 +57,11 @@ function diffstat {
 		/^-/       { if (scan) { r += 1 } next }
 		/^!/       { if (scan) { c += 1 } next }
 		END        {
-			dofile();
-			print "\t-----------------------------------total------------------";
-			print "\t+"at"\t-"rt"\t!"ct"\tin "n" files"
+			dofile()
+			print "\t----------------------------------------total------------------"
+			line(at, rt, ct, "\033[min "n" files")
 		}
-	' < $1
+	' <$1
 }
 
 
@@ -65,12 +70,13 @@ TMP=$(mktemp -d -t $SELF.$AIRCRAFT.XXX) || (echo "$0: can't create temporary dir
 trap "rm -rf $TMP" 0 1 2 3 13 15
 
 
-# move older archive or diff file out of the way
+# move older archive or diff files out of the way
 [ -f $DIFF ] && mv $DIFF $(mktemp $DIFF.X)
+[ -f $CDIFF ] && mv $CDIFF $(mktemp $CDIFF.X)
 [ -f $ARCHIVE ] && mv $ARCHIVE $(mktemp $ARCHIVE.X)
 
 
-LOG "updating and checking for changed and new files ..."
+LOG "updating and checking for new files ..."
 $CVS -q up -dP >$TMP/up
 
 
@@ -85,37 +91,36 @@ LOG "making diff ..."
 if ! $CVS -q diff -up >$DIFF; then
 	LOG "diff statistics:"
 	diffstat $DIFF
+	echo
 
 	# add diff file itself
-	echo $DIFF >>$TMP/include
+	echo $DIFF >>$TMP/files
 
 	# add changed binary files
 	awk '
-		/^Index: / { scan = 1; file = $2 }
-		/^@@/      { scan = 0 }
+		/^Index: / { scan = 1; file = $2; next }
+		/^@@/      { scan = 0; next }
 		/^Binary/  { if (scan) { print file } }
-	' <$DIFF >>$TMP/include
+	' <$DIFF >>$TMP/files
 else
 	rm -f $DIFF
 fi
 
 
-# write list of all files to add
-LOG "adding to archive ..."
-if [ -f $TMP/include ]; then
-	cat $TMP/include|while read i; do
-		ADD "$i"
-		echo $i >>$TMP/files
+LOG "checking for files to submit ..."
+if [ -f $TMP/files ]; then
+	cat $TMP/files|while read i; do
+		CHANGED "$i"
 	done
 fi
 grep "^? " $TMP/up|while read i; do
-	find ${i#? } -type f >>$TMP/files
+	find ${i#? } -type f >>$TMP/check
 done
 
 
 # classify and filter files
-if [ -f $TMP/files ]; then
-	for i in $(cat $TMP/files); do
+if [ -f $TMP/check ]; then
+	for i in $(cat $TMP/check); do
 		case "$i" in
 		$ARCHIVE*|$DIFF*) # don't add files generated by the script
 			;;
@@ -134,19 +139,29 @@ if [ -f $TMP/files ]; then
 			REJECT "$i\t\t(graphics file)"
 			;;
 		*)
-			ADD "$i"
-			echo "$i" >>$TMP/include
+			NEW "$i"
+			echo "$i" >>$TMP/files
 			;;
 		esac
 	done
 fi
 
 
-if [ -f $TMP/include ]; then
-	LOG "creating archive $ARCHIVE"
-	tar -cjf $ARCHIVE --files-from $TMP/include
+if ! [ -f $TMP/files ]; then
+	LOG "no changed or new files found"
+	exit 0
+fi
+
+echo
+numfiles=$(awk '//{n+=1}END{print n}' <$TMP/files)
+if [ -f $DIFF -a $numfiles == 1 ]; then
+	LOG "only changed non-binary files found"
+	LOG "creating compressed diff \e[1;37;40m$CDIFF\e[m\e[35m ..."
+	bzip2 -k $DIFF
 else
-	LOG "no changed or new files detected"
+	LOG "changed and/or new files found"
+	LOG "creating archive \e[1;37;40m$ARCHIVE\e[m\e[35m ..."
+	tar -cjf $ARCHIVE --files-from $TMP/files
 fi
 exit 0