---
name: linux-ssh-operator
description: 通过 SSH 连接并操作 Linux 服务器：执行远程命令、查看日志、管理 systemd 服务、传输文件（scp/rsync/tar/sftp）、排障。用户提到 ssh/scp/rsync、远程服务器 IP:端口、systemctl/journalctl、部署到服务器、在服务器上运行命令、远程拷贝文件 等场景时使用。
---

# Linux SSH Operator

## Goal

Use SSH for safe, repeatable Linux server operations.

## Fast Decision

1. Remote command or service check -> `scripts/ssh_run.sh`
2. Single file copy -> `scripts/ssh_copy.sh --method scp`
3. Directory sync or exclusions -> `scripts/ssh_copy.sh --method rsync -r`
4. Many small files -> `scripts/ssh_copy.sh --method tar`
5. If sudo may prompt -> add `--tty --sudo`

Prefer explicit method selection when the shape is already known. It is faster and avoids bad auto guesses.

## Before Acting

1. Confirm `host`, `port`, `user`, and auth method.
2. Prefer SSH keys and `~/.ssh/config` aliases.
3. Start with read-only checks, then change, then verify.
4. For first-connect automation, prefer `--accept-new` only when appropriate.
5. On flaky links, set `--connect-timeout` so failed attempts return fast.

## Command Runs

Use `ssh_run.sh` for non-interactive commands:

```bash
ssh_run.sh my-server -- uname -a
ssh_run.sh --tty --sudo my-server -- systemctl restart nginx
ssh_run.sh --sudo-non-interactive my-server -- systemctl status nginx --no-pager
```

Notes:

- `--sudo` is for commands that may prompt.
- `--sudo-non-interactive` is only for passwordless sudo paths.

## File Transfer

Use `ssh_copy.sh` for transfers:

```bash
ssh_copy.sh --method scp push my-server ./local.txt /tmp/local.txt
ssh_copy.sh --method rsync -r push my-server ./dir /tmp/dir
ssh_copy.sh --method tar push my-server ./many-small-files/ /tmp/
```

Rules:

- `--tar` is a packaging mode, not something to mix with `--method rsync/scp/sftp`.
- Use `--exclude` only with `rsync`.
- Use `--delete` only when you really want destination cleanup.

## Common Ops

- Disk: `df -h`, `du -sh /path/* | sort -h`
- Memory/CPU: `free -h`, `top`, `ps aux --sort=-%mem | head`
- Logs: `journalctl -u SERVICE -n 200 --no-pager`
- Services: `systemctl status|restart|stop SERVICE`
- Networking: `ss -lntp`, `ip a`, `ip r`

## Safety

- Never store passwords in repo files or chat logs.
- Avoid `StrictHostKeyChecking=no`.
- For destructive commands, ask for explicit confirmation and show the exact command first.

## References

- SSH security + troubleshooting: `references/ssh-playbook.md`

## Scripts

- `scripts/ssh_run.sh`: remote command execution with consistent options.
- `scripts/ssh_copy.sh`: file transfer via scp/rsync/tar/sftp with consistent options.