如何在Bash中成对循环$ @？

Question

如何在bash中编写循环，执行如下操作：

for (i=0; i< len("$@"); i+=2) {
    print a[i], a[i+1]
    // do stuff using the pair elements.
}

Answer 1

简单（和POSIX兼容）方法不是索引到$@，而是在开始时简单地将事情移开：

while [ "$#" -gt 0 ]; do
  echo "$1, $2"
  shift; shift
done

如果您确实想要编制索引，并且不介意特定于shell（如bash）采用ksh开创的扩展：

# start at 1 to avoid $0
# quotes in immediately below line because SO syntax highlighter doesn't know bash
for ((i=1; i<("$#" + 1); i+=2)); do
  echo "${@:i:1}, ${@:i+1:1}"
done