BASH数组索引减去最后一个数组 [英] BASH Array indexing minus the last array

问题描述

这是一个困扰我的问题-我需要从用户输入中读取版本号，并且我想使用存储版本号的数组的长度创建一个菜单".但是，BASH的神秘语法在这里没有帮助我

Here is a problem which bothers me - I need to read version number from user input, and I'd like to create a "menu" using the length of the array storing the version numbers. However, BASH's mysterious syntax is not helping me here:

echo $VERSIONS
2.0.10-1 2.0.7-1 2.0.7-1 2.0.7-1 2.0.10-1

for v in ${!VERSIONS[*]}
do
  echo "$(($v+1))) ${VERSIONS[$v]}  "
done

输出

1) 2.0.10-1
   2.0.7-1
   2.0.7-1
   2.0.7-1
   2.0.10-1  
2) 2.0.7-1  
3) 2.0.7-1  
4) 2.0.7-1  
5) 2.0.10-1   

另一个命令

for v in ${!VERSIONS[*]}
do
  echo "$(($v+1))) ${VERSIONS[$v+1]}  "
done

1) 2.0.7-1  
2) 2.0.7-1  
3) 2.0.7-1  
4) 2.0.10-1  
5)   

我真正想要的是这样的输出:

What I'd really like to have is an output like that:

1) 2.0.7-1  
2) 2.0.7-1  
3) 2.0.7-1  
4) 2.0.10-1 

不含最后5个)....

with out the last 5)....

很乐意在bash中阐明如何做...

Would be happy to unravel how to do it in bash...

P.S.我的一位同事刚刚提供了一种没有阵列的方法.我发布它只是为了好玩:

P.S. A colleague of mine just offered a way without arrays. I'm posting it just for fun:

i=1
for v in $VERSIONS
do
  echo "$i) $v" ; i=$(($i+1))
done

输出

1) 2.0.10-1
2) 2.0.7-1
3) 2.0.7-1
4) 2.0.7-1
5) 2.0.10-1

好的，由于解决方案无法在我的脚本内运行，因此我将发布更多信息:

OK, since the solutions don't work inside my script I will post some more info:

for package in $NEWPACKAGES 
do  
    apt-show-versions -a -p $package
    VERSIONS=$(apt-show-versions -a -p $package | cut -d ":" -f 2 | cut -d " " -f 1)
    echo $VERSIONS
    echo "type the number for version you want to install: (type enter to skip)"

    for i in `seq 1 ${#VERSIONS[@]}`; do 
    echo "$i) ${VERSIONS[$(($i-1))]}"; 
done

    echo $VERSIONS    
    read version
    echo "your choice $version"
    # now the problem is that i can't get this part to work !
    apt-get install $package="${#VERSIONS[$version]}"
done

推荐答案

一个包含数组的版本(如果仍需要的话).

A version with arrays, if you still need one.

for i in `seq 1 ${#VERSIONS[@]}`; do 
    echo "$i) ${VERSIONS[$(($i-1))]}"; 
done

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