Scripts & Runtime Examples

Examples for shell scripts, Python scripts, working directories, shell selection, and reproducible runtimes.

Shell Scripts

steps:
  - run: |
      #!/bin/bash
      cd /tmp
      echo "hello world" > hello
      cat hello
      ls -la

Run shell script with default shell.

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Shebang Script

tools:
  - astral-sh/uv@0.11.14

steps:
  - run: |
      #!/usr/bin/env -S uv run --python 3.13.9 python
      import platform
      print(platform.python_version())

Runs with the interpreter declared in the shebang.

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Python Scripts

tools:
  - astral-sh/uv@0.11.14

steps:
  - run: |
      import os
      import datetime
      
      print(f"Current directory: {os.getcwd()}")
      print(f"Current time: {datetime.datetime.now()}")
    with:
      shell: uv run --python 3.13.9 python

Execute script with specific interpreter.

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Multi-Step Scripts

steps:
  - run: |
      #!/bin/bash
      set -e
      
      echo "Starting process..."
      echo "Preparing environment"
      
      echo "Running main task..."
      echo "Running main process"
      
      echo "Cleaning up..."
      echo "Cleaning up"

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Distributed Script Files

steps:
  - id: generate_report
    run: bash scripts/report.sh config/report.yaml
    dependencies:
      - scripts/report.sh
      - config/report.yaml

Transfer a DAG-local script and its configuration when the workflow runs on a distributed worker.

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Working Directory

working_dir: /tmp
steps:
  - id: show_default_dir
    run: pwd               # Outputs: /tmp

  - id: create_data_dir
    run: mkdir -p data
    depends: show_default_dir

  - id: show_data_dir
    working_dir: /tmp/data
    run: pwd      # Outputs: /tmp/data
    depends: create_data_dir

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Shell Selection

shell: /bin/bash             # Default shell for all steps
shell_args: ["-e"]           # Default shell args for all steps
steps:
  - run: echo hello world | xargs echo
  - run: echo "from zsh"     # Override for a single step
    with:
      shell: /bin/zsh

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Reproducible Env with Nix Shell

Note: Requires nix-shell to be installed separately. Not included in Dagu binary or container.

steps:
  - run: |
      python3 --version
      curl --version
      jq --version
    with:
      shell: nix-shell
      shell_packages: [python3, curl, jq]

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