smy-skills/linux-ssh-operator-skill/SKILL.md

---
name: linux-ssh-operator-skill
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）、配置 SSH 别名、安装公钥启用免密登录、SSH 隧道/端口转发、跳板机、内网穿透、排障。用户提到 ssh/scp/rsync、远程服务器 IP:端口、配置 ssh 别名、ssh-copy-id、免密登录、systemctl/journalctl、部署到服务器、在服务器上运行命令、远程拷贝文件、SSH 隧道、端口转发、跳板机、堡垒机、服务器上看一下、帮我连上服务器、查看服务器日志 等场景时使用。

---

# Linux SSH Operator

## Overview

Use SSH to connect to Linux servers and perform safe, repeatable remote operations (commands, logs, services, file transfer, alias bootstrap, passwordless login, tunnels).

## Workflow

1. Confirm authorization and the target (host, port, user).
2. Prefer SSH keys (recommended) for non-interactive runs; avoid storing passwords in files or chat logs.
3. Start with read-only checks, then apply changes, then verify.
4. If a password prompt or interactive tool is required, run the SSH command in a real terminal/TTY (or enable TTY in your runner).

## Quick Start

### Set up SSH keys (recommended)

Generate a key (ed25519):

```bash
ssh-keygen -t ed25519 -C "codex" -f ~/.ssh/id_ed25519
```

Install the public key on the server (example uses port 22):

```bash
ssh-copy-id -i ~/.ssh/id_ed25519.pub -p 22 USER@SERVER_IP
```

Optional: create an alias in `~/.ssh/config`:

```sshconfig
Host my-server
  HostName SERVER_IP
  Port 22
  User USER
  IdentityFile ~/.ssh/id_ed25519
  IdentitiesOnly yes
```

Then connect:

```bash
ssh my-server
```

### Bootstrap alias + passwordless login

When the user provides an alias, host/IP, and password and wants `ssh alias` to work immediately:

1. Write or update the alias with the helper script:

```bash
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_alias_setup.sh my-server 192.168.1.10 --user root --install-key
```

2. If `ssh-copy-id` prompts for a password, run in a TTY and enter the password once.
3. Verify passwordless login:

```bash
ssh -o BatchMode=yes my-server 'echo SSH_OK; id -un 2>/dev/null || echo root'
```

4. Remind the user that `scp` and `rsync` can reuse the same alias:

```bash
scp ./file.txt my-server:/root/
rsync -av ./dir/ my-server:/root/dir/
```

Notes:

- `scripts/ssh_alias_setup.sh` auto-generates `~/.ssh/id_ed25519` if it does not exist.
- It updates `~/.ssh/config` idempotently and defaults to `root`, port `22`, and `StrictHostKeyChecking=accept-new`.
- For tests, set `SSH_CONFIG_FILE=/path/to/temp-config`.

### Run remote commands

- Direct:

```bash
ssh my-server uname -a
```

- With sudo (often needs a TTY):

```bash
ssh -tt my-server sudo systemctl status nginx --no-pager
```

- Via wrapper script (consistent options; supports env defaults like `REMOTE_USER`, `REMOTE_PORT`, `REMOTE_KEY`):
  - If you installed this Skill globally in `~/.claude/skills/`, use the absolute paths below (recommended so both Claude Code + OpenCode can find it).

```bash
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_run.sh my-server -- uname -a
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_run.sh --tty --sudo my-server -- systemctl restart nginx
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_run.sh --compress my-server -- cat /var/log/big.log
```

### Transfer files

Upload (scp):

```bash
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_copy.sh push my-server ./local.txt /tmp/local.txt
```

Download (scp):

```bash
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_copy.sh pull my-server /var/log/syslog ./syslog
```

Incremental sync (rsync — preferred for directories or large files):

```bash
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_copy.sh --rsync push my-server ./dist/ /var/www/html/
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_copy.sh --rsync --delete push my-server ./dist/ /var/www/html/
~/.claude/skills/linux-ssh-operator-skill/scripts/ssh_copy.sh --rsync pull my-server /var/log/ ./logs/
```

### SSH Tunneling / Port Forwarding

Local forward (access remote service on a local port):

```bash
# Access remote MySQL (3306) at localhost:13306
ssh -L 13306:127.0.0.1:3306 my-server -N
```

Remote forward (expose a local port on the server):

```bash
# Make local :8080 accessible on server's :18080
ssh -R 18080:127.0.0.1:8080 my-server -N
```

Jump host (bastion → target):

```bash
ssh -J bastion-user@bastion:22 target-user@target-host
```

Or configure in `~/.ssh/config`:

```sshconfig
Host target-internal
  HostName 10.0.0.50
  User ubuntu
  ProxyJump bastion
```

### SSH Multiplexing (faster repeated connections)

Add to `~/.ssh/config` to reuse the same TCP connection:

```sshconfig
Host *
  ControlMaster auto
  ControlPath ~/.ssh/ctrl-%h-%p-%r
  ControlPersist 60s
```

The first `ssh my-server` opens a master connection; subsequent connections reuse it without re-handshaking.

## Common Ops (snippets)

- 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`, `tail -n 200 -f /path/log`
- Services: `systemctl status|restart|stop|enable SERVICE`
- Networking: `ss -lntp`, `ip a`, `ip r`, `curl -v http://127.0.0.1:PORT/`
- Docker: `docker ps`, `docker logs -f CONTAINER`, `docker exec -it CONTAINER bash`
- Config test: `nginx -t`, `sshd -T`
- Open files: `lsof -i :PORT`, `fuser PORT/tcp`

## Safety

- Never store or paste passwords in repo files or chat logs.
- Avoid `StrictHostKeyChecking=no`; prefer verifying host keys (or use `accept-new` only when appropriate).
- For destructive commands (rm, shutdown, firewall changes), ask for explicit user confirmation and show the exact command first.

## References

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

## Scripts

- `scripts/ssh_alias_setup.sh`: create/update SSH aliases and optionally run `ssh-copy-id`.
- `scripts/ssh_run.sh`: run remote commands with consistent options (supports `--compress`, `--tty`, `--sudo`).
- `scripts/ssh_copy.sh`: push/pull files via scp or rsync (use `--rsync` for incremental transfers).