Which command is used to save the current configuration in Junos OS?

The command "commit" is used in Junos OS to save the current configuration. When this command is executed, it takes the changes made in the candidate configuration (which is a temporary workspace where configuration changes can be edited safely) and applies them to the active configuration running on the device. This means that all changes are preserved and become effective immediately.

This process ensures that the current operational state of the device reflects the desired configuration specified by the user. It's an essential step in maintaining network device reliability and ensuring that configurations persist through reboots.

Other commands listed do not function in the same way in Junos OS. For instance, "save" is not a recognized command in this context. The command "copy running-config" is found in other operating systems, but it does not apply to Junos. "write memory" is also associated with different systems, primarily for saving configuration on Cisco devices, but it does not represent the correct command in the Junos OS environment. Thus, "commit" is uniquely suited to achieving the task of saving configuration within Junos.