Memory monitoring and usage management are one of the critical system administrator requirement. It’s always required to keep the system under monitoring to check if memory is low or any user or process is over-consuming it. Linux comes up with multiple commands that you can use to monitor and manage the usage. Different ways to check memory usage:- Free: Free command gives details of memory used, free, cache and total. By default values are in KB but you can pass -m to have values in MB. /proc/meminfo: This is a system file to monitor memory. It will give you 6 entries Total Active RAM, Total Inactive RAM, User Active RAM, User Inactive RAM, File Active RAM & File Inactive RAM. Vmstat: VMSTATS give you memory statistics. Top: Top command gives you memory usage and total RAM. This command also used for monitoring. A staple in advanced Linux interview questions with answers, be prepared to answer this one using your hands-on experience. This is also one of the top interview questions to ask a Linux developer.