suppress output for md5sum

Makefile

@@ -37,6 +37,7 @@ DVIPS	= dvips
 PDFPS	= pdftops
 PDF	= max_print_line=1000 pdflatex -shell-escape -src -halt-on-error -synctex=1 -interaction nonstopmode -file-line-error-style
 OPEN    = xdg-open
+MD5SUM  = md5sum --quiet
 
 # Mac-specific definitions
 ifeq ($(shell uname), Darwin)
@@ -85,7 +86,7 @@ edit: $(SRCNAMES)
 	$(BIBTEX) $(@:.bbl=.aux) | true
 
 	@echo Flush the citation hash
-	test -s $(@:.pdf=.cit) || echo '' | md5sum > $(@:.pdf=.cit)
+	test -s $(@:.pdf=.cit) || echo '' | $(MD5SUM) > $(@:.pdf=.cit)
 
 %.aux : %.pdf;
 
@@ -96,13 +97,13 @@ edit: $(SRCNAMES)
 	$(LATEX) $(@:.dvi=.tex) || (touch --date="`date -R -r $(@:.dvi=.tex)`" $@ & false)
 
 	@echo If the citations were updated recompile the .bbl file
-	grep -o -G "Citation \`[^']*" $(@:.dvi=.log) | md5sum -c $(@:.dvi=.cit) || $(BIBTEX) $(@:.dvi=.aux)
+	grep -o -G "Citation \`[^']*" $(@:.dvi=.log) | $(MD5SUM) -c $(@:.dvi=.cit) || $(BIBTEX) $(@:.dvi=.aux)
 
 	while grep -q "Rerun to get cross-references right." $(@:.dvi=.log); \
 	do $(LATEX) $(@:.dvi=.tex); done
 
 	@echo Update the missing citation hash
-	grep -o -G "Citation \`[^']*" $(@:.dvi=.log) | md5sum > $(@:.dvi=.cit)
+	grep -o -G "Citation \`[^']*" $(@:.dvi=.log) | $(MD5SUM) > $(@:.dvi=.cit)
 
 %.pdf: %.tex	# Cancel the default rule
 
@@ -118,10 +119,10 @@ edit: $(SRCNAMES)
   fi
 
 	@echo Create $(@:.pdf=.cit) if it does not exist
-	test -s $(@:.pdf=.cit) || echo '' | md5sum > $(@:.pdf=.cit)
+	test -s $(@:.pdf=.cit) || echo '' | $(MD5SUM) > $(@:.pdf=.cit)
 
 	@echo If the citations were updated recompile the .bbl file
-	grep -o -G "Citation \`[^']*" $(@:.pdf=.log) | md5sum -c $(@:.pdf=.cit) || ($(BIBTEX) $(@:.pdf=.aux); $(PDF) $(@:.pdf=.tex) >/dev/null)
+	grep -o -G "Citation \`[^']*" $(@:.pdf=.log) | $(MD5SUM) -c $(@:.pdf=.cit) || ($(BIBTEX) $(@:.pdf=.aux); $(PDF) $(@:.pdf=.tex) >/dev/null)
 
 	@echo -n "Search for dangling references.. "
 	@if grep -q "Rerun to get cross-references right." $(@:.pdf=.log); \
@@ -134,7 +135,7 @@ edit: $(SRCNAMES)
 	fi
 
 	@echo Update the citation hash
-	grep -o -G "Citation \`[^']*" $(@:.pdf=.log) | md5sum > $(@:.pdf=.cit)
+	grep -o -G "Citation \`[^']*" $(@:.pdf=.log) | $(MD5SUM) > $(@:.pdf=.cit)
 
 %.ps : %.pdf
 	$(PDFPS) -level1 $<  		# Create .ps from .pdf