wget command

Synopsis

wget [address] [host:]path
wget [address] url          # lwIP only

Description

The wget command is used to download a file from an HTTP(S) server. In order to use HTTPS you will need to compile wget with lwIP support.

Legacy syntax

The legacy syntax is supported by the legacy network stack (CONFIG_NET=y) as well as by the lwIP base network stack (CONFIG_NET_LWIP=y). It supports HTTP only.

By default the destination port is 80 and the source port is pseudo-random. On the legacy nework stack the environment variable httpdstp can be used to set the destination port

address: memory address for the data downloaded
host: IP address (or host name if CONFIG_CMD_DNS is enabled) of the HTTP server, defaults to the value of environment variable serverip.
path: path of the file to be downloaded.

New syntax (lwIP only)

In addition to the syntax described above, wget accepts URLs if the network stack is lwIP.

address: memory address for the data downloaded
url: HTTP or HTTPS URL, that is: http[s]://<host>[:<port>]/<path>.

Examples

Example with the legacy network stack

In the example the following steps are executed:

setup client network address
download a file from the HTTP server

=> setenv autoload no
=> dhcp
BOOTP broadcast 1
*** Unhandled DHCP Option in OFFER/ACK: 23
*** Unhandled DHCP Option in OFFER/ACK: 23
DHCP client bound to address 192.168.1.105 (210 ms)
=> wget ${loadaddr} 192.168.1.254:/index.html
HTTP/1.0 302 Found
Packets received 4, Transfer Successful

Example with lwIP

In the example the following steps are executed:

setup client network address
download a file from the HTTPS server

=> dhcp
DHCP client bound to address 10.0.2.15 (3 ms)
=> wget https://download.rockylinux.org/pub/rocky/9/isos/aarch64/Rocky-9.4-aarch64-minimal.iso
##########################################################################
##########################################################################
##########################################################################
[...]
1694892032 bytes transferred in 492181 ms (3.3 MiB/s)
Bytes transferred = 1694892032 (65060000 hex)

Configuration

The command is only available if CONFIG_CMD_WGET=y. To enable lwIP support set CONFIG_NET_LWIP=y.

TCP Selective Acknowledgments in the legacy network stack can be enabled via CONFIG_PROT_TCP_SACK=y. This will improve the download speed. Selective Acknowledgments are enabled by default with lwIP.

Note

U-Boot currently has no way to verify certificates for HTTPS. A place to store the root CA certificates is needed, and then MBed TLS would need to walk the entire chain. Therefore, man-in-the middle attacks are possible and HTTPS should not be relied upon for payload authentication.

Return value

The return value $? is 0 (true) on success and 1 (false) otherwise.