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Check RAM Usage with free -h

Use free -h to see used, free, and available memory plus swap in GB/MiB instead of raw kilobytes.

LinuxmonitoringmemoryfreeLow risk
Run `free -h` to display memory and swap usage in human-readable units.

01Command

Command
$ free -h

02What it does

The 'available' column is the number that matters for 'can I run another app' — it estimates how much memory can be reclaimed without swapping. 'free' is memory the kernel isn't using at all and is usually tiny because Linux borrows unused RAM for disk caches. Run `free -h -s 2` to refresh every 2 seconds, or `free -h -w` to split buffers and cache into separate columns.

03Risk

RiskLow risk

04Undo

✓No undo needed — this command does not change persistent state.

05Sources

  • free(1) - Linux manual page
    Ubuntu Manpages · technical · 2026-09-17
    Evidence: free displays the total amount of free and used physical and swap memory, and -h shows all output fields automatically scaled to human-readable units.

Last verified: 2026-09-17 · Category: System & Settings

06Related solutions

Snapshot System Health with vmstat
Linuxvmstatmonitoringperformance

vmstat gives a compact one-line-per-interval view of CPU usage, swap activity, and I/O waits that top doesn't summarize as clearly.

Low risk ✓ 2026-09-17