Any recommendations for a command-line download manager?
Solution 1:
wget, that is installed by default, has such a feature through the -c option:
-c
--continue
Continue getting a partially-downloaded file. This is useful when
you want to finish up a download started by a previous instance of
Wget, or by another program.
...
Note that -c only works with FTP servers and with HTTP servers that
support the "Range" header.