$ mage.sh -u *.c > Makefile 
Makefile -> /tmp/.mage.sh.432.mak
1
new file: dlist.c
1
new file: filter.c
1
new file: getaline.c
1
new file: hash.c
1
new file: main.c
1
new file: memdbg.c
1
new file: parser.c

$ mage.sh -u *.c            
Makefile -> /tmp/.mage.sh.1120.mak
0
old file: dlist.c
0
old file: filter.c
0
old file: getaline.c
0
old file: hash.c
0
old file: main.c
0
old file: memdbg.c
0
old file: parser.c

UpdateNew () {
    # updates include only cc stuff
    for file in $(echo "$1" | sed 's/:/ /g') ; do
	if [ ! -r "$file" ]; then
		Warn "Could not open - '$file'"
		continue
	fi
	if $(grep -q '^'${file%.*}'[$](OBJ):' "${tmp}.mak"); then
	  echo $? 1>&2
	  Notify "old file: $file"
	  old="$old$file:"
	else
	  echo $? 1>&2
	  Notify "new file: $file"
	  new="$new$file:"
	fi
    done
    MkDepend "$old"
    EmitCC "$new"
}