1 2set -- a b c d e f g h i j 3[ "$1" = a ] || echo "error at line $LINENO" 4[ "${1}" = a ] || echo "error at line $LINENO" 5[ "${1-foo}" = a ] || echo "error at line $LINENO" 6[ "${1+foo}" = foo ] || echo "error at line $LINENO" 7[ "$1+foo" = a+foo ] || echo "error at line $LINENO" 8[ "$10" = a0 ] || echo "error at line $LINENO" 9[ "$100" = a00 ] || echo "error at line $LINENO" 10[ "${10}" = j ] || echo "error at line $LINENO" 11[ "${10-foo}" = j ] || echo "error at line $LINENO" 12[ "${100-foo}" = foo ] || echo "error at line $LINENO" 13