The run keyword is identical to runwait except that it does not wait for command to complete.
command is the path name of the command to be run. run does not fail unless it is unable to create a child process to execute the command.
Although they are syntactically indistinguishable, some of the commands available to run and runwait are interpreter built-in commands. Interpreter built-ins are used when it is necessary to alter the state of a process within the context of that process. The doconfig() interpreter built-in commands are similar to the shell special commands and, like these commands, they do not spawn another process for execution. See the sh(1) man page. The initial set of built-in commands is: