假设我将一些数据读入Bash数组：
$IFS=" " read -a arr <<< "hello/how are/you iam/fine/yeah"
现在,我想为数组中的每个元素打印第一个/ -sliced字段.
我所做的是遍历元素并使用shell参数扩展来从第一个/中删除所有内容：
$for w in "${arr[@]}"; do echo "${w%%/*}"; done
hello
are
iam
但是,由于printf允许我们在一个表达式中打印数组的整个内容：
$printf "%s\n" "${arr[@]}"
hello/how
are/you
iam/fine
…我想知道在使用printf时是否有办法使用shell参数扩展${w %% / *},而不是循环遍历所有元素并对每一个元素进行操作.
哦,我刚刚找到了方法：正常使用参数扩展,只针对${arr [@]}而不是${arr}！
$IFS=" " read -a arr <<< "hello/how are/you iam/fine/yeah"
$printf "%s\n" "${arr[@]%%/*}"
hello
are
iam
格雷格的维基帮助了这里：
07000
BASH arrays are remarkably flexible,because they are well integrated@H_404_27@ with the other shell expansions. Any parameter expansion that can be@H_404_27@ carried out on a scalar or individual array element can equally apply@H_404_27@ to an entire array or the set of positional parameters such that all@H_404_27@ members are expanded at once,possibly with an additional operation@H_404_27@ mapped across each element.
06001
