Solved: How to Automate on Systems Without PowerShell

Understanding the Symptoms: Why Can’t I Run PowerShell?

Many Windows systems present limitations preventing PowerShell execution, impacting automation efforts. These limitations include legacy operating systems, security restrictions via Group Policy, resource constraints on embedded devices, non-standard Windows builds, and strict compliance requirements – leading to manual tasks, errors, and operational bottlenecks.

Why This Matters

While PowerShell is the standard for Windows automation, assuming its availability is unrealistic. Ideal models assume homogenous environments, but the reality is diverse, often including systems with limited capabilities. Failing to address these limitations leads to increased operational costs, higher error rates from manual intervention, and security vulnerabilities due to inconsistent configurations.

Key Insights

• PowerShell execution policy restrictions are common: Organizations frequently block PowerShell execution for security reasons, even on systems where it’s installed.
• Batch scripting remains relevant: Despite its age, Batch scripting provides a baseline for automation on almost any Windows system.
• Python offers portability and power: Python can be deployed without installation, providing a modern scripting environment where PowerShell is unavailable, as utilized in numerous automation projects.

Working Example

# C:\Python\python.exe C:\scripts\check_disk.py
import os
import sys
def get_drive_space(drive):
"""
Get total, used, and free space for a given drive letter.
Returns (total_gb, used_gb, free_gb) or None on error.
"""
if not os.path.exists(drive):
return None
try:
# Use os.statvfs for POSIX-like systems, or fallback to subprocess for Windows
# For simplicity on older Windows without pywin32, we can call WMIC.
# This example directly calculates from a subprocess call to WMIC.
cmd = f'wmic logicaldisk where caption="{drive}" get size,freespace /value'
process = os.popen(cmd)
output = process.read()
process.close()
size_str = None
freespace_str = None
for line in output.splitlines():
if line.startswith("FreeSpace="):
freespace_str = line.split("=")[1]
elif line.startswith("Size="):
size_str = line.split("=")[1]
if size_str and freespace_str:
total_bytes = int(size_str)
free_bytes = int(freespace_str)
used_bytes = total_bytes - free_bytes
# Convert to GB for readability
total_gb = round(total_bytes / (1024**3), 2)
used_gb = round(used_bytes / (1024**3), 2)
free_gb = round(free_bytes / (1024**3), 2)
return (total_gb, used_gb, free_gb)
else:
return None
except Exception as e:
print(f"Error getting space for {drive}: {e}", file=sys.stderr)
return None
if __name__ == "__main__":
DRIVE_LETTER = "C:" # Or any other drive, e.g., "D:"
WARNING_THRESHOLD_GB = 10 # Alert if free space below 10GB
WARNING_THRESHOLD_PERCENT = 15 # Alert if free space below 15%
space_info = get_drive_space(DRIVE_LETTER)
if space_info:
total, used, free = space_info
free_percent = (free / total) * 100 if total > 0 else 0
print(f"Drive: {DRIVE_LETTER}")
print(f"Total Space: {total} GB")
print(f"Used Space: {used} GB")
print(f"Free Space: {free} GB ({free_percent:.2f}%)")
if free <= WARNING_THRESHOLD_GB or free_percent <= WARNING_THRESHOLD_PERCENT:
print(f"WARNING: Low disk space on {DRIVE_LETTER}!")
# Add logic here to trigger an alert (e.g., call a batch script to send email)
sys.exit(1) # Indicate an error for external orchestration
else:
print(f"Disk space on {DRIVE_LETTER} is healthy.")
sys.exit(0)
else:
print(f"Could not retrieve disk space for {DRIVE_LETTER}", file=sys.stderr)
sys.exit(1)

Practical Applications

• Legacy Server Management: Maintaining automated patching or monitoring on older Windows Server versions where PowerShell is outdated or unavailable.
• Pitfall: Relying solely on PowerShell scripts for automation across all systems, leading to failures when encountering unsupported environments.

References:

• https://dev.to/techresolve/solved-how-to-automate-stuff-on-a-system-that-cant-run-ps-scripts-9kk