Reliable Excel Workbook Creation via Shell

When to Use This Pattern

Use this technique when you need to:

• Create complex Excel workbooks with multiple sheets
• Perform multi-step workbook operations (create, populate, format, save)
• Work with XLSX files that read_file cannot handle properly
• Avoid failures from execute_code_sandbox on persistent file operations

Avoid: read_file for XLSX files, execute_code_sandbox for multi-step workbook creation

Core Pattern

cd /workspace && python3 << 'EOF'
from openpyxl import Workbook
# Your Excel operations here
wb = Workbook()
# ... create sheets, add data, save
wb.save('/workspace/filename.xlsx')
EOF

Step-by-Step Instructions

Step 1: Change to Workspace Directory

Always start with cd /workspace && to ensure file paths resolve correctly.

Step 2: Use Heredoc with Single-Quoted EOF

Use << 'EOF' (single quotes) to prevent shell variable expansion within the Python code.

Step 3: Write Complete Python Script

Include all imports, workbook creation, data population, and save operations in one script.

Step 4: Use Absolute Paths for Save Operations

Always save with full path: /workspace/your_filename.xlsx

Complete Example

cd /workspace && python3 << 'EOF'
from openpyxl import Workbook
from openpyxl.styles import Font, Alignment, PatternFill

# Create workbook
wb = Workbook()

# Create multiple sheets
sheets = ['Summary', 'Data', 'Analysis', 'Settings']
for sheet_name in sheets:
    wb.create_sheet(title=sheet_name)

# Remove default sheet if needed
if 'Sheet' in wb.sheetnames:
    del wb['Sheet']

# Populate data
ws = wb['Data']
ws['A1'] = 'Item'
ws['B1'] = 'Value'
ws['A2'] = 'Revenue'
ws['B2'] = 100000

# Apply formatting
header_font = Font(bold=True)
for cell in ws['1:1']:
    cell.font = header_font

# Save workbook
wb.save('/workspace/report.xlsx')
print('Workbook created successfully: /workspace/report.xlsx')
EOF

Why This Works

Approach	Problem	Solution
read_file	Cannot parse XLSX binary format	Don't use for Excel files
execute_code_sandbox	File persistence issues, multi-step failures	Use run_shell instead
run_shell with heredoc	✓ Reliable, full control, persistent files	Use this pattern

Common Operations

Create Multi-Sheet Workbook

cd /workspace && python3 << 'EOF'
from openpyxl import Workbook
wb = Workbook()
sheet_names = ['Sheet1', 'Sheet2', 'Sheet3']
for name in sheet_names:
    wb.create_sheet(title=name)
wb.save('/workspace/multi_sheet.xlsx')
EOF

Read and Modify Existing Workbook

cd /workspace && python3 << 'EOF'
from openpyxl import load_workbook
wb = load_workbook('/workspace/existing.xlsx')
ws = wb.active
ws['A1'] = 'Updated Value'
wb.save('/workspace/existing.xlsx')
EOF

Add Formulas

cd /workspace && python3 << 'EOF'
from openpyxl import Workbook
wb = Workbook()
ws = wb.active
ws['A1'] = 100
ws['A2'] = 200
ws['A3'] = '=SUM(A1:A2)'
wb.save('/workspace/with_formulas.xlsx')
EOF

Troubleshooting

• File not found: Ensure you use /workspace/ prefix in all paths
• Permission errors: Verify workspace directory is writable
• Module not found: openpyxl is pre-installed in the environment
• Heredoc issues: Use single-quoted 'EOF' to prevent shell interpretation

Best Practices

1. Always use absolute paths (/workspace/filename.xlsx)
2. Single-quoted heredoc (<< 'EOF') prevents variable expansion
3. Complete script in one heredoc - avoid splitting operations
4. Print confirmation after save to verify success
5. Handle exceptions for production scripts