name1 = name1-value name2 = ${name1?name 1 defined, |$name1|$name2|} ${name1:name 1 undefined, |$name1|$name2|} ${name2?name 2 defined, |$name1|$name2|} ${name2:name 2 undefined, |$name1|$name2|} |$name1|$name2| $(name1 $(name ) name2 = name2-value ${name1?name 1 defined, |$name1|$name2|} ${name1:name 1 undefined, |$name1|$name2|} ${name2?name 2 defined, |$name1|$name2|} ${name2:name 2 undefined, |$name1|$name2|} |$name1|$name2|