带有变量的Linux lftp mv命令

Question

I'm trying to read file name from a txt file and move files in a FTP server from one folder to another. I have the following command

grep '.rar' /home/xxxxx/public_html/xxxx/download.txt | while read -r line ; do lftp -e 'set net:timeout 20; mv "Folder Name/${line}" "Folder Name/tmp/${OUTPUT}"; bye' -u username,password ftps://11.11.11.11:990 ; done

However, the ${$line} variable is not being replaced with values and the FTP server is showing

file/directory not found (Folder Name/${line})

Any pointer would be appreciated. (I'm on Centos 6.5 if that helps).

Answer 1

You have the whole command single quoted, which prevents bash parameter expansion within. You can fix that part by reversing the single and double quotes like so:

grep '.rar' /home/xxxxx/public_html/xxxx/download.txt | while read -r line ; do lftp -e "set net:timeout 20; mv 'Folder Name/${line}' 'Folder Name/tmp/${OUTPUT}'; bye" -u username,password ftps://11.11.11.11:990 ; done

Assuming you have no files with newlines or single quotes this should work I expect.

To help protect against special characters you can use printf instead of just directly expanding in place like:

grep '.rar' /home/xxxxx/public_html/xxxx/download.txt | while read -r line ; do lftp -e "set net:timeout 20; mv '$(printf 'Folder Name/%q' "${line}")' '$(printf 'Folder Name/tmp/%q' "${OUTPUT}")'; bye" -u username,password ftps://11.11.11.11:990 ; done

since we can use printf with %q to print a quoted/escaped string that can be used in the next layer of command