-BUILDS=($(curl -s https://api.travis-ci.org/repos/simgrid/simgrid/builds/${BUILD_NUM} | grep -o '{"id":[0-9]*,' | grep -o '[0-9]*'| tail -n 3))
-OS=($(curl -s https://api.travis-ci.org/repos/simgrid/simgrid/builds/${BUILD_NUM} | grep -o '"os":"[a-z]*",' | sed 's/"os":"\([a-z]*\)",/\1/g'| tail -n 3))
+BUILDS=($(curl -s https://api.travis-ci.org/repos/simgrid/simgrid/builds/"${BUILD_NUM}" | grep -o '{"id":[0-9]*,' | grep -o '[0-9]*'| tail -n 3))
+OS=($(curl -s https://api.travis-ci.org/repos/simgrid/simgrid/builds/"${BUILD_NUM}" | grep -o '"os":"[a-z]*",' | sed 's/"os":"\([a-z]*\)",/\1/g'| tail -n 3))