free

Overview

The free command displays the amount of free and used memory in the system. It shows information about both physical and swap memory.

Syntax

free [options]

Common Options

Option	Description
`-b`	Bytes
`-k`	Kilobytes
`-m`	Megabytes
`-g`	Gigabytes
`-h`	Human readable
`-w`	Wide output
`-s N`	Repeat every N sec
`-c N`	Repeat N times
`-t`	Show total
`-l`	Show low/high

Output Fields

Field	Description
total	Total memory
used	Used memory
free	Unused memory
shared	Shared memory
buff/cache	Buffer/cache
available	Available memory

Key Use Cases

Memory monitoring
System resources
Performance analysis
Capacity planning
Troubleshooting

Examples with Explanations

Example 1: Basic Usage

free

Show memory info

Example 2: Human Readable

free -h

Easy to read format

Example 3: Continuous

free -s 5

Update every 5 seconds

Common Usage Patterns

Quick check:
```
free -h
```
Monitor changes:
```
free -s 1 -c 10
```
Total memory:
```
free -t
```

Memory Types

Physical memory
Swap memory
Buffer memory
Cache memory
Shared memory

Additional Resources

Best Practices

Regular checks
Use human readable
Monitor trends
Check available
Document usage

Performance Analysis

Memory usage
Swap usage
Buffer usage
Cache usage
Available memory

Troubleshooting

Low memory
High swap
Cache usage
Memory leaks
System performance

Common Issues

Memory pressure
Swap thrashing
Cache problems
Memory fragmentation
Resource exhaustion