如何在ash中使用数组？

Question

由于某些原因，我不能使用bash来构建我的脚本，唯一的方法是使用ash，我有这个短信自动回复脚本，每个回复必须是最多160个字符的长度，它看起来是这样的：

#!/bin/sh
    reply="this is a reply message that contains so many words so I have to split it to some parts"
    array="${reply:0:5} ${reply:5:5} ${reply:10:5} ${reply:15:5} ${reply:20:5}"
    for i in $array
    do
    echo "send sms with the message: $i"
    done

但它最终是这样的：

send sms with the message: this
send sms with the message: is
send sms with the message: a
send sms with the message: reply
send sms with the message: mess
send sms with the message: age
send sms with the message: t

我想要的是这样的：

send sms with the message: this 
send sms with the message: is a 
send sms with the message: reply
send sms with the message: messa
send sms with the message: ge th
send sms with the message: at co
send sms with the message: ntain

所以它是按字符数拆分，而不是按单词拆分，我该怎么做呢？

Answer 1

您的数组实际上不是一个数组，但请阅读http://mywiki.wooledge.org/WordSplitting以了解有关这方面的更多信息。

ash本身并不支持数组，但您可以通过使用set来规避这一点

reply="this is a reply message that contains so many words so I have to split it to some parts"
set -- "${reply:0:5}" "${reply:5:5}" "${reply:10:5}" "${reply:15:5}" "${reply:20:5}"
for i; do
        echo "send sms with the message: $i"
done

-

send sms with the message: this
send sms with the message: is a
send sms with the message: reply
send sms with the message:  mess
send sms with the message: age t

对此有许多替代解决方案，其中之一是使用fold为您完成拆分工作，并增加了一个优点，即它可以在空格上换行，使消息更具可读性(请参阅man fold了解更多信息)：

reply="this is a reply message that contains so many words so I have to split it to some parts"
echo "${reply}" | fold -w 10 -s | while IFS= read -r i; do
        echo "send sms with the message: $i"
done

-

send sms with the message: this is a
send sms with the message: reply
send sms with the message: message
send sms with the message: that
send sms with the message: contains
send sms with the message: so many
send sms with the message: words so
send sms with the message: I have to
send sms with the message: split it
send sms with the message: to some
send sms with the message: parts