如何解决 curl：（6）无法解析主机 [重复]答案

【问题标题】：How to resolve curl: (6) Couldn't resolve host [duplicate]如何解决 curl：（6）无法解析主机 [重复]
【发布时间】：2020-06-19 14:19:07
【问题描述】：

我正在尝试在循环中使用 curl 调用 rest api，如下所示。它不起作用并抛出错误curl: (6) Couldn't resolve host '$SERVERPROTOCOL:' 但是，如果替换所有环境变量并执行命令，那么它就可以正常工作。

有效的直接命令：

curl -X DELETE -k -H 'Content-Type: application/xml' -H 'Accept: application/xml' -u 'testuser:test123' -i 'https://nonprodhost:443/process/cancel/pvm:0a126'

Curl 在循环中抛出 - curl: (6) Couldn't resolve host '$SERVERPROTOCOL:'

for pi in $(cat $halted_pid);do
    # write PID to console so user knows script is working
    echo
    echo "cacnelling process instance - $pi"
    # 2>&1 to include any output on stderr
    curl -X DELETE -k -H 'Content-Type: application/xml' -H 'Accept: application/xml' -u '$USERNAME:USERPASS' -i '$SERVERPROTOCOL://$SERVERHOST:$SERVERPORT/process/cancel/$pi' 2>&1 | tee -a $halted_pi_cancellation_logfile
done

【问题讨论】：

Bash 不会在单引号中插入变量。您可能还需要括号：stackoverflow.com/questions/17622106/…

标签： bash curl

【解决方案1】：

为什么我认为问题是单引号？尝试用双引号替换单引号

（参考：https://www.php.net/manual/en/language.types.string.php#language.types.string.syntax.double）

curl -X DELETE -k -H 'Content-Type: application/xml' -H 'Accept: application/xml' -u '$USERNAME:USERPASS' -i '$SERVERPROTOCOL://$SERVERHOST:$SERVERPORT/process/cancel/$pi' 2>&1 | tee -a $halted_pi_cancellation_logfile

转换为：

curl -X DELETE -k -H "Content-Type: application/xml" -H "Accept: application/xml" -u "$USERNAME:USERPASS" -i "$SERVERPROTOCOL://$SERVERHOST:$SERVERPORT/process/cancel/$pi" 2>&1 | tee -a $halted_pi_cancellation_logfile

【讨论】：