在shell中，以点分隔符分割字符串的一部分 [英] In shell, split a portion of a string with dot as delimiter

问题描述

我是Shell脚本的新手，请帮忙满足以下要求，谢谢.

I am new to shell scripting, can you please help with below requirement, thanks.

$AU_NAME=AU_MSM3-3.7-00.01.02.03
#separate the string after last "-", with "." as delimiter
#that is, separate "00.01.02.03" and print/save as below.
major=00
minor=01
micro=02
build=03

推荐答案

首先，请注意，在外壳程序中分配参数时，请勿使用$.您的第一行应该是这样:

First, note that you don't use $ when assigning to a parameter in the shell. Your first line should be just this:

AU_NAME=AU_MSM3-3.7-00.01.02.03

一旦有了，就可以做这样的事情:

Once you have that, then you can do something like this:

IFS=. read major minor micro build <<EOF
${AU_NAME##*-}
EOF

其中，##*-将从字符串的开头到最后一个'-'剥离所有内容，仅留下"00.01.02.03"，而IFS(内部字段分隔符)变量告诉Shell将字符串分成何处字段.

where the ##*- strips off everything from the beginning of the string through the last '-', leaving just "00.01.02.03", and the IFS (Internal Field Separator) variable tells the shell where to break the string into fields.

在bash，zsh和ksh93 +中，您可以通过将here-document缩短为here-string来将其放在一行上:

In bash, zsh, and ksh93+, you can get that onto one line by shortening the here-document to a here-string:

IFS=. read major minor micro build <<<"${AU_NAME##*-}"

更一般而言，在那些相同的shell(或任何其他具有数组的shell)中，您可以拆分为任意大小的数组，而不是单独的变量.可以在给定的shell中使用:

More generally, in those same shells (or any other shell that has arrays), you can split into an arbitrarily-sized array instead of distinct variables. This works in the given shells:

IFS=. components=(${AU_NAME##*-})

在旧版本的ksh中，您可以执行以下操作:

In older versions of ksh you can do this:

IFS=. set -A components ${AU_NAME##*-}

这使您具有等效性(zsh除外，默认情况下，zsh将元素编号为1-4而不是0-3):

That gets you this equivalence (except in zsh, which by default numbers the elements 1-4 instead of 0-3):

major=${components[0]}
minor=${components[1]}
micro=${components[2]}
build=${components[3]}

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