如何在Bash中将本地变量加载到关联数组中？

If you want to automatically gather specific local variables (like var1, var2, var3) into an associative array without manually listing each one, you can leverage Bash's local -p command to list local variables in the current scope, then parse those lines to extract names and values.

Here's a practical implementation tailored to your use case:

#!/bin/bash

function build_vars_array() {
    # Define your local variables first (these are the ones you want to collect)
    local var1="db_username=admin"
    local var2="nginx_root=/var/www/app"
    local var3="sql_port=5432"
    local temp_var="skip_this" # Example variable to exclude from the array

    # Initialize the target associative array
    declare -A vars_list

    # Loop through all local variable declarations in the current scope
    while IFS= read -r line; do
        # Skip variables that don't match your naming pattern (varN)
        if [[ ! "$line" =~ ^local\ var[0-9]+= ]]; then
            continue
        fi

        # Extract the variable name (e.g., var1 from "local var1='value'")
        local var_name=$(echo "$line" | sed -E 's/^local ([^=]+)=.*/\1/')
        
        # Safely retrieve the variable's value using indirect expansion
        local var_value="${!var_name}"

        # Add the key-value pair to the associative array
        vars_list["$var_name"]="$var_value"
    done < <(local -p) # Feed local variable list into the loop (avoids subshell issues)

    # Optional: Verify the array contents
    echo "Collected variables for templating:"
    for key in "${!vars_list[@]}"; do
        echo "$key: ${vars_list[$key]}"
    done
}

# Execute the function
build_vars_array

How This Works: #

1. local -p: This command outputs all local variables in the current function scope in the format local var_name='value', which we can parse.
2. Pattern Matching: The regex ^local\ var[0-9]+= filters only variables named var1, var2, etc., skipping any other local variables you don't want to include.
3. Indirect Expansion: ${!var_name} safely retrieves the value of the variable whose name is stored in var_name—this is a secure alternative to using eval for variable interpolation.
4. Associative Array: We populate vars_list with each matching variable's name as the key and its value as the value, ready for use in templating SQL/Nginx files.

Customization Tips: #

• If you want to include all local variables except the array itself, adjust the skip condition to:

  if [[ "$line" =~ ^local\ vars_list= ]]; then
      continue
  fi
  

• Modify the regex pattern to match your actual variable naming convention (e.g., ^local\ app_ for variables starting with app_).

This approach keeps your script maintainable—you won't have to update the array manually every time you add a new variable.

内容的提问来源于stack exchange，提问作者Alexi Theodore