free
free is a Linux command in the System Info category, rated intermediate difficulty. Displays memory usage (RAM + swap). The syntax is free [options]. It returns memory usage statistics. A practical example: free -h # Human-readable output free -m # Output in megabytes free -s 2 # Repeat every 2 seconds A close relative is uname, which displays system information (kernel name, hostname, architecture). A close relative is df, which reports disk space usage for mounted filesystems. A close relative is du, which estimates file and directory space usage. More about this category: Linux system info commands — uname, df, du, free, uptime, lscpu, and more. View system information and hardware details. Related System Info commands: uname, df, du, uptime, lscpu, lsusb, lspci, hostname. This page is part of the free Linux Reference documentation covering 304+ commands, each with syntax, options, practical examples, and a difficulty rating.