# lsof Cheatsheet - Cheatsheets - Launch Pad

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# lsof Cheatsheet

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lsof (list open files) shows information about files opened by processes. Lists open files, network connections, and file descriptors. Essential for debugging and system administration.

## Basic Usage

- lsof - List all open files

- lsof -p PID - Files by process

- lsof -u user - Files by user

- lsof file - Processes using file

- lsof -i - Network connections

## Process Selection

- -p PID - Process ID

- -p PID1,PID2 - Multiple PIDs

- -p ^PID - Exclude PID

- -c command - Command name

- -u user - Username

- -u ^user - Exclude user

## File Selection

- lsof file - Specific file

- lsof +D directory - Directory

- lsof +d directory - Directory (non-recursive)

- -a - AND conditions

- -t - Show only PIDs

## Network Options

- -i - All network connections

- -i TCP - TCP connections

- -i UDP - UDP connections

- -i :port - Specific port

- -i @host - Specific host

- -i @host:port - Host and port

- -i TCP:port - TCP on port

- -i UDP:port - UDP on port

## Output Options

- -F - Field output

- -l - Show login names

- -n - No hostname resolution

- -P - No port name resolution

- -t - PID only

- -w - Suppress warnings

- -V - Version

## Common Examples

### Process Files

    lsof -p 1234

Files opened by process.

### User Files

    lsof -u username

Files opened by user.

### File Usage

    lsof /path/to/file

Processes using file.

### Network Connections

    lsof -i

All network connections.

### Port Usage

    lsof -i :80

Process using port 80.

### TCP Connections

    lsof -i TCP

All TCP connections.

### Specific Host

    lsof -i @192.168.1.1

Connections to/from host.

### Command Files

    lsof -c firefox

Files opened by command.

### Directory Files

    lsof +D /var/log

Files in directory.

### PID Only

    lsof -t -i :80

Get PID using port.

## Tips

- Use -i for network troubleshooting

- Use -t to get PIDs for scripts

- Use -n and -P for faster output

- Combine with kill to free resources

- Use -a to combine conditions

- Essential for debugging file locks

- Great for finding port conflicts

- Useful for security auditing