为何脚本在Kali Linux可正常运行，在Ubuntu却无法执行？

核心错误分析 #

1. 管道语法错误：脚本中curl ... | $(python3 -c "...")的写法完全错误。$(...)会先执行Python命令（此时无stdin输入直接报错），再将空结果作为命令执行，导致curl输出无法传递给Python。
2. HTTP2协议兼容性问题：Ubuntu默认curl启用HTTP2，与Cloudflare API交互时触发协议错误，导致无有效JSON输出。
3. 变量边界模糊：$OPTARG.emailtesting.co.uk会被Shell解析为$OPTARG.emailtesting变量，而非预期的$OPTARG拼接.emailtesting.co.uk。
4. Shell变量侵入Python代码：Python代码用双引号包裹时，Shell会替换其中的$domainName，破坏正则表达式逻辑。
5. 依赖缺失：addSubDomain函数依赖jq，Ubuntu默认未安装该工具。

修复步骤 #

1. 修正管道语法 #

将所有| $(python3 -c "...")改为| python3 -c "..."，让curl输出直接流向Python进程。

2. 强制curl使用HTTP1.1 #

在所有curl命令中添加--http1.1参数，解决HTTP2协议错误：

curl --http1.1 -X GET "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records" ...

3. 明确变量边界 #

将$OPTARG.emailtesting.co.uk改为${OPTARG}.emailtesting.co.uk，用大括号限定变量范围。

4. 隔离Shell变量与Python代码 #

将Python代码改用单引号包裹，需要传递的Shell变量用'"$VARNAME"'形式注入，避免Shell提前替换：

# 原错误写法
re.sub(r'(.+)($domainName)$',r'\1',line)
# 修正后
domain = '"$domainName"'
re.sub(r"(.+)(" + domain + r")$", r"\1", line)

5. 安装缺失依赖 #

执行以下命令安装所需工具：

sudo apt update && sudo apt install -y jq python3

修改后的完整脚本 #

#!/bin/bash

# Imported variables
source <(grep -E '^\w+=' /root/scripts/variables.sh)
ZONE_ID=$zoneID
cloudflareAPItoken=$cloudflareAPItoken
domainName=$domainName
serverName=$servername

function help {
    echo "This is the help test"
}

findID () {
    curl --http1.1 -X GET "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records" \
    -H "Authorization: Bearer $cloudflareAPItoken" \
    -H 'Content-Type: application/json' \
    | python3 -c "import sys,json
data=json.loads(sys.stdin.read())

if data['success']:
    for item in data['result']:
        if item['name']=='${OPTARG}.emailtesting.co.uk':
            f = open('demofile.txt', 'w')
            f.write(item['id'])
            f.close()" 
}


deleteDNS () {
    curl --http1.1 -X DELETE "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records/$(cat demofile.txt)" \
    -H "Authorization: Bearer $cloudflareAPItoken" \
    -H "Content-Type: application/json" \
    | python3 -m json.tool;
    rm demofile.txt 
}


listAllDNS () {
    curl --http1.1 -X GET "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records" \
    -H "Authorization: Bearer $cloudflareAPItoken" \
    -H 'Content-Type: application/json' \
    | python3 -c 'import sys,json, re
data=json.loads(sys.stdin.read())
f = open("dnsLIST.txt", "w")
if data["success"]:
    for dict in data["result"]:
        if dict["type"] == "A" and dict["name"] != '"$domainName"':           
            f.write(dict["name"] + "\n")

            
else:
    print("ERROR(" + str(data["errors"][0]["code"]) + "): " + data["errors"][0]["message"])
    
f.close()

fin = open("dnsLIST.txt", "r")
fout = open("dnsLISTredone.txt", "w")

domain = '"$domainName"'
for line in fin:
    new_line = re.sub(r"(.+)(" + domain + r")$", r"\1", line)
    new_line = new_line.rstrip("\n") + "\n"
    fout.write(new_line)
fin.close()
fout.close()
    
'

}


addSubDomain () {
    curl --http1.1 -s -X POST "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records" \
    -H "Authorization: Bearer $cloudflareAPItoken" \
    -H "Content-Type: application/json" \
    --data "{\"type\":\"A\",\"name\":\"$OPTARG\",\"content\":\"$serverName\",\"ttl\":120,\"proxied\":false}" | jq
}

if [[ ${#} -eq 0 ]]; then
    help
    exit 1
fi

optstring="hd:la:"
while getopts ${optstring} arg; do
    case ${arg} in
        h)
            help;;
        d)
            findID
            deleteDNS
            exit 1
            ;;
        l) 
            listAllDNS;;
        a)
            addSubDomain;;
        ?)
            echo "Invalid option: -${OPTARG}."
            exit 2;;
    esac
done

内容的提问来源于stack exchange，提问作者Tim Biermann