free
display memory usage statistics
TLDR
Display system memory
$ free
Display memory in human-readable units$ free -h
Display memory in megabytes$ free -m
Display memory in gigabytes$ free -g
Refresh the output every 2 seconds$ free -s 2
Display totals line$ free -t
Display wide output separating buffers and cache$ free -hw
Repeat output every 2 seconds, 5 times$ free -s 2 -c 5
SYNOPSIS
free [-b|-k|-m|-g] [-h] [-s delay] [-c count] [-t]
DESCRIPTION
free displays the total amount of free and used physical and swap memory in the system, as well as the buffers and caches used by the kernel. The information is gathered from /proc/meminfo.
PARAMETERS
-b
Display in bytes-k
Display in kilobytes (default)-m
Display in megabytes-g
Display in gigabytes-h, --human
Display in human-readable format with units-s, --seconds delay
Continuously display output every delay seconds-c, --count count
Display output count times (use with -s)-t, --total
Display a line showing totals-w, --wide
Wide output (separate buffers and cache)-l, --lohi
Show detailed low and high memory statistics
INSTALL
sudo apt install procps
sudo dnf install procps-ng
sudo pacman -S procps-ng
sudo apk add procps-ng
sudo zypper install procps
brew install procps
nix profile install nixpkgs#procps
CAVEATS
The "available" memory column (added in Linux 3.14) is a better estimate of how much memory is available for starting new applications. "Free" memory doesn't account for buffers/cache that can be released.
HISTORY
Part of the procps (or procps-ng) package, which provides process monitoring utilities for Linux.