curl/docs/cmdline-opts/parallel.md

c	SPDX-License-Identifier	Short	Long	Help	Added	Category	Multi	Scope	See-also	Example
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.	curl	Z	parallel	Perform transfers in parallel	7.66.0	connection curl	boolean	global	next verbose parallel-max parallel-immediate	--parallel $URL -o file1 $URL -o file2

--parallel

Makes curl perform all transfers in parallel as compared to the regular serial manner. Parallel transfer means that curl runs up to N concurrent transfers simultaneously and if there are more than N transfers to handle, it starts new ones when earlier transfers finish.

With parallel transfers, the progress meter output is different than when doing serial transfers, as it then displays the transfer status for multiple transfers in a single line.

The maximum amount of concurrent transfers is set with --parallel-max and it defaults to 50.