Which command would you use to check free memory and high RAM usage?

Using the free command is the most straightforward way to check free memory and assess high RAM usage in a Linux system. When executed, this command provides a summary of the total, used, free, shared, buff/cache, and available memory, giving a clear view of how memory resources are being utilized at that moment.

The output includes key metrics like the total amount of physical memory, the space currently in use, and the space that is freely available for use by applications. This makes it easy to identify potential memory pressure or excessive use of RAM, helping administrators understand memory usage patterns and troubleshoot performance issues.

Other options serve different purposes. For instance, while vmstat provides a variety of statistics related to processes, memory, paging, block IO, traps, and CPU activity, it does not present memory information in as simple a format as free. The mkswap command is specifically used to set up swap space on a device, which is unrelated to checking current memory usage. Load average, typically shown in several system monitoring commands, indicates the number of processes in the run queue, not the amount of free or used memory.