Resuming a partial download prevents a dropped session from wasting already transferred bytes. That matters most for large artifacts, unstable links, and unattended jobs where starting over can add minutes or hours to a recovery step.
GNU wget resumes with -c or --continue by reusing the existing local file and requesting the remaining bytes from the server. When the remote endpoint supports byte ranges, the next request returns HTTP 206 Partial Content and appends only the missing portion.
Server support is the key requirement. If the remote side ignores range requests, current wget builds restart the download from the beginning and overwrite the existing partial file, so confirm Accept-Ranges support before you rely on resume behavior for important artifacts.
$ cd ~/downloads/resume $ ls -lh sample-256k.bin -rw-r--r-- 1 user user 64K Mar 27 06:57 sample-256k.bin
Resume works against the existing filename in the current directory, so do not rename the partial file before rerunning the command.
$ wget -c https://downloads.example.net/files/sample-256k.bin
--2026-03-27 06:57:54-- https://downloads.example.net/files/sample-256k.bin
Connecting to downloads.example.net (downloads.example.net)|203.0.113.50|:443... connected.
HTTP request sent, awaiting response... 206 Partial Content
Length: 262144 (256K), 196608 (192K) remaining [application/octet-stream]
Saving to: 'sample-256k.bin'
[ skipping 50K ]
50K ,,,,,,,,,, ,,,,...... .......... .......... .......... 39% 561M 0s
...
2026-03-27 06:57:54 (619 MB/s) - 'sample-256k.bin' saved [262144/262144]
A 206 Partial Content response confirms that the server accepted the range request and only sent the missing bytes.
$ wget --server-response --spider https://downloads.example.net/files/sample-256k.bin 2>&1 | grep -iE 'HTTP/|Accept-Ranges' HTTP/1.1 200 OK Accept-Ranges: bytes
If the response lacks Accept-Ranges: bytes, wget -c can restart from byte zero and overwrite the partial file instead of appending to it.
$ rm -f sample-256k.bin $ wget https://downloads.example.net/files/sample-256k.bin
Deleting the partial file is irreversible, so verify the path and filename before you remove it.
$ ls -lh sample-256k.bin
-rw-r--r-- 1 user user 256K Mar 27 06:57 sample-256k.bin
$ wget -c https://downloads.example.net/files/sample-256k.bin
--2026-03-27 07:00:38-- https://downloads.example.net/files/sample-256k.bin
Connecting to downloads.example.net (downloads.example.net)|203.0.113.50|:443... connected.
HTTP request sent, awaiting response... 416 Requested Range Not Satisfiable
The file is already fully retrieved; nothing to do.
Pair the size check with a published checksum when the artifact will be executed or unpacked later.