How to run wget downloads in the background

Large downloads fetched from remote Linux systems often run for minutes or hours, which makes them vulnerable to interruptions when a terminal closes or an SSH connection drops. Running wget in the background keeps long transfers alive while other commands continue, which is useful for pulling large ISO images, backups, or log archives over unreliable or slow links.

On Ubuntu and other Linux distributions, wget works as a non-interactive downloader that speaks HTTP, HTTPS, and FTP and writes directly to regular files. Background execution can rely on the shell’s job control, the native wget option -b, or helpers such as nohup that detach the process from its controlling terminal. Sending progress messages into a dedicated log file keeps diagnostic output available without tying up the terminal.

Even when detached, background transfers still run under the same user account and consume local disk space and network bandwidth. Unmonitored downloads can fill a filesystem or saturate a shared link, so choosing a directory with sufficient free space and keeping track of progress logs matters. For transfers that must survive SSH disconnections or logouts, combining wget with nohup and explicit logging provides resilience while preserving a clear record of the download.

1. Open a terminal on the Linux system where the background download should run.

   $ whoami
   user

2. Change into the directory that should receive the downloaded file to keep paths predictable.

   $ cd ~/Downloads

   Placing downloads under a dedicated directory such as /home/user/Downloads keeps large files away from critical system partitions.

3. Start a background download with wget using the -b option and a dedicated log file for progress output.

   $ wget -b -o ubuntu-24.04.iso.log -O ubuntu-24.04.iso https://releases.ubuntu.com/24.04/ubuntu-24.04-live-server-amd64.iso
   Continuing in background, pid 12345.
   Output will be written to 'ubuntu-24.04.iso.log'.

   The -b option tells wget to detach into the background immediately, while -O sets the output filename and -o stores progress and error messages in the specified log file.

4. Verify that the background wget process is active by searching the process list.

   $ ps aux | grep '[w]get'
   user      12345  5.2  0.3  89960  3100 pts/0    S    10:15   0:03 wget -b -o ubuntu-24.04.iso.log -O ubuntu-24.04.iso https://releases.ubuntu.com/24.04/ubuntu-24.04-live-server-amd64.iso

   The bracketed character in the grep pattern prevents the grep process itself from matching and appearing in the output.

5. Monitor download progress by following the log file until the transfer reaches a suitable completion point.

   $ tail -f ubuntu-24.04.iso.log
   --2025-05-13 10:15:01--  https://releases.ubuntu.com/24.04/ubuntu-24.04-live-server-amd64.iso
   Resolving releases.ubuntu.com (releases.ubuntu.com)... 185.125.190.39
   Connecting to releases.ubuntu.com (releases.ubuntu.com)|185.125.190.39|:443... connected.
   HTTP request sent, awaiting response... 200 OK
   Length: 2149580800 (2.0G) [application/x-iso9660-image]
   Saving to: ‘ubuntu-24.04.iso’
   
   ubuntu-24.04.iso   21% [====>                  ] 457,457,664  9.85MB/s    eta 3m 0s
   ##### snipped #####

   Press Ctrl+C to stop following the log; the background download continues running until it completes or encounters an error.

6. Run the transfer under nohup when the background download must continue after the terminal or SSH session closes.

   $ nohup wget -O ubuntu-24.04.iso https://releases.ubuntu.com/24.04/ubuntu-24.04-live-server-amd64.iso >> ubuntu-24.04.iso.log 2>&1 &
   [1] 23456

   Long-running downloads can quickly consume bandwidth and disk space; always point wget at a filesystem with sufficient free space and avoid running unnecessary background transfers.

7. Confirm completion by checking the final file size and modification time once the log file stops growing.

   $ ls -lh ubuntu-24.04.iso
   -rw-r--r-- 1 user user 2.0G May 13 10:30 ubuntu-24.04.iso

   Successful background downloads typically show a final summary line in the log file along with the expected size in the directory listing.