all-groenn.tex: exercise/*.tex
for m in $$(grep -rl '% category: green' exercise/ |grep '.tex$$'|sed 's/.tex$$//'); do echo "\include{$$m}"; done > all-groenn.tex.new && mv all-groenn.tex.new all-groenn.tex
all-groenn.tex: exercise/*.tex
for m in $$(grep -rl '% category: green' exercise/ |grep '.tex$$'|sed 's/.tex$$//'); do echo "\include{$$m}"; done > all-groenn.tex.new && mv all-groenn.tex.new all-groenn.tex