（为了回应评论，我对此进行了多次编辑）

我的目标是创建一个shell脚本，该脚本连接到外部服务器，从目录中获取一批文件，在热敏收据打印机上打印这些文件，然后从远程服务器删除相同的文件（这样当cron作业运行时，就不会再打印这些文件）。我的问题是将一个变量连接到cURL的URL末尾。脚本的其余部分正在工作，但为了清晰起见，我将显示整个脚本

我已经为解决方案做了几次搜索，许多似乎涉及更复杂的情况，例如，这一个试图解决隐藏的回车，因为变量被追加到URL的中间（C.F.Bash CURL和URL中间的变量）。我尝试了那个解决方案（还有其他几个），但都不起作用。我的情况比较简单（我想），所以这些答案可能会增加不必要的复杂性，这就是我的问题？无论如何。。。

以下是敏感信息占位符的完整代码：

!/bin/bash
# step 1 - change to the directory where we want to temporarily store tickets
cd Tickets
# step 2 - get all the tickets in the target directory on the external server and put them in the current temporary local directory
wget --secure-protocol TLSv1_2 --user=<placeholder> --password='<placeholder>d' ftps://<placeholder>/public_html/tickets/*.txt
# step 3 - print each of the tickets in the current temporary local directory
for i in *.txt
do lp $i
done
# step 4 - reach out to the target directory and delete each of the files that we previously downloaded (not the entire directory; might have new files)
for i in *.txt
do curl --verbose --ftp-ssl --user <placeholder>:<placeholder> 'ftp://<placeholder>/public_html/tickets' -Q "DELE /public_html/tickets/$i"
done
# empty the current local directory where we temporarily stored files during the execution of this script
for i in *.txt
do rm $i
done
# should be done now.

我在步骤4中使用了以下所有变体：

for i in *.txt
do curl --ftp-ssl --user (myftpid):(mypasswd) ftp://(myhostname)/public_html/tickets/ -Q 'DELE /public_html/tickets/'$i
done

for i in *.txt
do curl --ftp-ssl --user (myftpid):(mypasswd) ftp://(myhostname)/public_html/tickets/ -Q 'DELE /public_html/tickets/'${i}
done

for i in *.txt
do curl --ftp-ssl --user (myftpid):(mypasswd) ftp://(myhostname)/public_html/tickets/ -Q 'DELE /public_html/tickets/'"$i"
done

for i in *.txt
do curl --ftp-ssl --user (myftpid):(mypasswd) ftp://(myhostname)/public_html/tickets/ -Q 'DELE /public_html/tickets/'"${i}"
done

所有这四项的输出为：

curl: (21) QUOT command filed with 550

通过测试，我能够确认代码在没有变量的情况下工作：

curl --ftp-ssl --user <placeholder>:<placeholder> ftp://<placeholder>/public_html/tickets/ -Q 'DELE /public_html/tickets/14.txt'

***编辑**我重新阅读了评论，我想我最初误解了其中一些。我可以在curl命令前面使用echo来查看变量的输出。这很有帮助，谢谢@Bodo。来自@National Bonless的关于冗长标签的建议也很有用，并产生了以下内容：

< 220-You are user number 1 of 50 allowed.
< 220-Local time is now 18:34. Server port: 21.
< 220-This is a private system - No anonymous login
< 220-IPv6 connections are also welcome on this server.
< 220 You will be disconnected after 30 minutes of inactivity.
AUTH SSL
< 500 This security scheme is not implemented
AUTH TLS
< 234 AUTH TLS OK.
* successfully set certificate verify locations:
*   CAfile: none
  CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / <placeholder>
* Server certificate:
*  subject: CN=<placeholder>
*  start date: Nov 16 00:00:00 2020 GMT
*  expire date: Nov 16 23:59:59 2021 GMT
*  subjectAltName: host "<placeholder>" matched cert's "<placeholder>"
*  issuer: C=US; ST=TX; L=Houston; O=cPanel, Inc.; CN=cPanel, Inc. Certification Authority
*  SSL certificate verify ok.
USER <placeholder>
< 331 User <placeholder> OK. Password required
PASS <placeholder>
< 230 OK. Current restricted directory is /
PBSZ 0
< 200 PBSZ=0
PROT P
< 200 Data protection level set to "private"
PWD
< 257 "/" is your current location
* Entry path is '/'
DELE /public_html/tickets/14.txt
* ftp_perform ends with SECONDARY: 0
< 550 Could not delete /public_html/tickets/14.txt: No such file or directory
* QUOT command failed with 550
* Closing connection 0