通过用户输入设置变量，并在继续脚本之前检查所有变量是否已设置

Question

好的，首先是几个明显的问题。扩展到以空格分隔的${script_variables[@]}整个数组。因此，当您在脚本开头定义数组时， $script_variables您将始终看到错误，因此永远不会为空。当您想引用数组的元素时，需要使用特定的数字索引：第一个元素，第二个元素等。test -z "${script_variables[@]}""${script_variables[@]}""${script_variables[0]}""${script_variables[1]}"

其次，当你将read一个值存入变量时，你需要将它存储在变量中。但是，您给出的read扩展数组只是存储在数组中的值：

$ echo "${script_variables[@]}"
admin_user_name admin_user_password

更重要的是，您似乎希望将用户给出的值存储在一个变量中，然后您可以通过名称调用该变量。这是您设置var="foo"然后拥有variableName="var"并试图获取的值多变的命名var（因此，在本例中为“foo”）称为“间接扩展”。其语法是${!variableName}.例如：

$ var="foo"
$ variableName="var"
$ echo "${!variableName}"
foo

因此，您可以使用它，也可以使用两个数组：一个用于存储变量名称，另一个用于存储它们的值。或者，对于现代版本的 bash 来说更好的是，使用单个关联数组其键将是变量名称。这是使用间接扩展的脚本的工作版本：

#/bin/bash

script_variables=(
    admin_user_name
    admin_user_password
)

## This will be used to exit the loop
allSet="";

while [[ -z $allSet ]]; do
  for varName in "${script_variables[@]}"; do 
    ## No need to loop the whole thing, just loop
    ## until this particular variable has been set
    while [[ -z ${!varName} ]]; do
      read -p "Enter value for $varName: " $varName
    done
  done

  ## We will only exit the loop once all vars have been set.
  ## Now print and check them.
  printf '\n=========\nYou have entered:\n'
  for varName in "${script_variables[@]}"; do 
    printf '%s=%s\n' "$varName" "${!varName}"
  done

  while true; do
    read -p "Are the variables correct? " yn
    case $yn in
      [Yy]* )
        echo "All variables have been set. The script will now continue.";
        ## Setting this to 1 exits the top "while [[ -z $allSet ]]; do" loop
        allSet=1
        break;;
      [Nn]* )
        ## Clear the stored values to start again
        for varName in "${script_variables[@]}"; do
          unset $varName
        done
        
        break;;
      * )
        echo "Please answer yes or no.";;
    esac
  done
done

这是使用关联数组的版本：

#/bin/bash

declare -A script_variables=(
    [admin_user_name]=""
    [admin_user_password]=""
)

## This will be used to exit the loop
allSet="";

while [[ -z $allSet ]]; do
  ## '${!array[@]}' returns all keys of an associative array
  for varName in "${!script_variables[@]}"; do
    read -p "Enter value for $varName: " script_variables[$varName]
  done

  ## We will only exit the loop once all vars have been set.
  ## Now print and check them.
  printf '\n=========\nYou have entered:\n'
  for varName in "${!script_variables[@]}"; do 
    printf '%s=%s\n' "$varName" "${script_variables[$varName]}"
  done

  while true; do
    read -p "Are the variables correct? " yn
    case $yn in
      [Yy]* )
        echo "All variables have been set. The script will now continue.";
        ## Setting this to 1 exits the top "while [[ -z $allSet ]]; do" loop
        allSet=1
        break;;
      [Nn]* )
        ## Clear the stored values to start again
        for varName in "${!script_variables[@]}"; do
          script_variables[$varName]=""
        done
        
        break;;
      * )
        echo "Please answer yes or no.";;
    esac
  done
done

现在，就我个人而言，我会使用稍微不同的方法。我不会设置所有内容，然后让用户最后检查，而是在输入时检查所有内容。这样，您就可以在一开始就得到错误，并且不需要重新设置所有变量，而只需重新设置出错的变量。像这样的东西：

#/bin/bash

declare -A script_variables=(
    [admin_user_name]=""
    [admin_user_password]=""
)

allSet=0;

while [[ $allSet -lt ${#script_variables[@]} ]]; do
  for varName in "${!script_variables[@]}"; do
        ok=""
        while [[ $ok != [Yy]* ]]; do
          read -p "Enter value for $varName: " script_variables[$varName]
          read -p "You entered '${script_variables[$varName]}'. Is this correct? " ok
        done
        ## If we're satisfied, increment the value of allSet
        ((allSet++))
  done
done

## You can add a second test here, but just exit the script if it's wrong.
## There's no point in complicating your code if you're just going back to
## the beginning anyway: just exit and rerun it.
printf '\n=========\nYou have entered:\n'
for varName in "${!script_variables[@]}"; do 
  printf '%s=%s\n' "$varName" "${script_variables[$varName]}"
done

read -p "Is everything OK? (y/n; n will exit the script)": yn
if [[ $yn != [Yy]* ]]; then
   exit
fi

echo "Everything correctly set, continuing!"

Answer 1