Bash 如何解决旋度：（6）不能'；不解析主机

我试图在循环中使用curl调用RESTAPI，如下所示。它不工作并抛出错误

curl:（6）无法解析主机“$SERVERPROTOCOL:”

然而，若替换所有环境变量并执行命令，那个么它就可以正常工作

工作的直接命令：

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

循环中的Curl抛出-

Curl:（6）无法解析主机“$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

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为什么我认为问题是单引号？尝试用双引号替换单引号

（参考资料：）

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

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Bash不在单引号中插入变量。您可能还需要括号：

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