I see some strange behaviour when trying to use ftp -T to conditionally download a file if it has changed. This is ftp from 7.8.
Here is an example to illustrate it, beginning with the non-working version: Header send by server: % curl -ILs https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/If-Modified-Since | grep -i last-modified last-modified: Thu, 02 Apr 2026 01:11:07 GMT Timestamp after downloading: % ftp -V https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/If-Modified-Since >/dev/null; stat -x If-Modified-Since| grep Modify Modify: Thu Apr 2 03:11:07 2026 Using ftp -T when fetching again: % ftp -T https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/If-Modified-Since Trying 151.101.37.91... Requesting https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/If-Modified-Since 100% |*******************************************************| 201 KB 00:00 206655 bytes received in 0.02 seconds (6.96 MB/s) % ftp -T https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/If-Modified-Since Trying 151.101.37.91... Requesting https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/If-Modified-Since 100% |*******************************************************| 201 KB 00:00 206655 bytes received in 0.02 seconds (7.27 MB/s) Here are the exact same commands with httpd as server which works as expected: % curl -ILs https://rkta.de/index.html | grep -i last-modified Last-Modified: Fri, 26 Dec 2025 09:36:01 UTC % ftp -V https://rkta.de/index.html >/dev/null; stat -x index.html| grep Modify Modify: Fri Dec 26 10:36:01 2025 % ftp -T https://rkta.de/index.html Trying 46.23.93.159... Requesting https://rkta.de/index.html ftp: File is not modified on the server What am I doing wrong here?
