Core CLI Usage

Session Modes

# Interactive mode (default)
claude

# One-shot mode — exits after task completes
claude -p "write a hello world function"

# Pipe mode — reads from stdin
cat app.log | claude -p "analyze this error"
git diff    | claude -p "review these changes"

Sessions

claude --resume            # pick from session list (or --resume <name>)
claude --continue          # resume the most recent session here
claude -n auth-refactor    # start a named session
claude --continue --fork-session   # branch off the last session
claude --from-pr 142       # resume the session that created PR #142
claude --teleport          # pull a web/mobile session into this terminal

Details: 08-sessions-and-checkpointing.md

Key Flags

Model & Reasoning

claude --model fable                  # most capable (Fable 5)
claude --model opus                   # complex reasoning (Opus 4.8)
claude --model sonnet                 # daily coding (Sonnet 5)
claude --model haiku                  # fast/cheap
claude --model opusplan               # Opus plans, Sonnet executes
claude --effort high                  # more reasoning (low/medium/high)

Output & Logging

claude --verbose                      # show full tool inputs/outputs
claude --output-format json           # full JSON at end
claude --output-format stream-json    # streaming JSON
claude --output-format md             # markdown only (no UI)

Permissions & Safety

claude --permission-mode plan         # read-only / plan mode
claude --permission-mode acceptEdits  # auto-approve file edits
claude --dangerously-skip-permissions # skip all prompts (sandboxes/containers only!)
claude --allowedTools "Bash(npm *),Read,Edit"
claude --disallowedTools "Bash(rm *),Bash(sudo *)"

Context & Scope

claude --max-turns 10                 # max interactions before exit
claude --add-dir /another/path        # grant access to additional directory
claude --no-files-in-context          # don't load project files at start
claude --cwd /path/to/project         # set working directory

System Prompt Customization

# Replace the system prompt entirely
claude --system-prompt "You are a security auditor. Find vulnerabilities."

# Append to the default system prompt
claude --append-system-prompt "Always use pnpm, not npm."

Integrations

claude --chrome                       # browser automation (see 39-slack-chrome-channels.md)
claude --channels plugin:telegram@claude-plugins-official   # push events in
claude --teammate-mode auto           # agent team display mode
claude mcp list                       # manage MCP servers from the shell
claude update                         # update Claude Code
claude doctor                         # diagnostics

Common One-Liners

# Fix lint errors non-interactively
claude -p "fix all lint errors" --permissions acceptEdits

# Analyze logs
tail -100 app.log | claude -p "what went wrong?"

# Review a PR diff
git diff main | claude -p "code review" --output-format md

# Generate JSON list
claude -p "list all exported functions in src/" --output-format json | jq '.[]'

🧠 Quick Recall

• Trick: “p prints, c continues, r resumes, n names.”
• Pipes work both ways: logs in → insight out.

👨‍🏫 Teach It

• Show: git diff | claude -p "review this" — one line, real value.
• They’ll trip on: flag names — it’s --permission-mode, and bypass is --dangerously-skip-permissions.

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Learning path: ⬅ 02-quickstart-first-session.md · Index · ➡ 04-slash-commands.md