Which command can be used to display system uptime?

The command that displays system uptime is commonly known as "uptime." This command provides a quick summary of how long the system has been running since the last boot, alongside information about the number of logged-in users and the load averages over the last 1, 5, and 15 minutes. Running this command will effectively show you the time elapsed since the last restart of the system, which is essential for system monitoring and management tasks.

The alternative commands you might consider serve different purposes. For example, "who" is used to list users currently logged into the system, while "top" displays a dynamic view of system processes, including CPU and memory usage, but does not directly show uptime. The "time" command is generally used to measure the duration of command execution rather than reporting system uptime. Thus, "uptime" stands out as the most directly relevant command for obtaining information about how long the system has been operational.