There are ways to run commands in parallel that are not built into Bash. GNU Parallel is a tool to do just that.
GNU Parallel, as its name suggests, can be used to build and run commands
in parallel. You may run the same command with different arguments, whether
they are filenames, usernames, hostnames, or lines read from files. GNU
Parallel provides shorthand references to many of the most common operations
(input lines, various portions of the input line, different ways to specify
the input source, and so on). Parallel can replace
xargs or feed
commands from its input sources to several different instances of Bash.
For a complete description, refer to the GNU Parallel documentation, which is available at https://www.gnu.org/software/parallel/parallel_tutorial.html.