如何用Python替代awk和sort获取RHEL服务器上XYZ软件的唯一版本号

Hey there! Let's walk through how to replace your shell-based pipeline with native Python code to get the unique version number of your XYZ software components. Here's a step-by-step solution:

Step 1: Fetch RPM Package List #

First, we'll use Python's subprocess module to get the output of rpm -qa, then filter for packages related to XYZ (no need for grep!):

import subprocess

# Execute rpm command and capture output
try:
    result = subprocess.run(
        ["rpm", "-qa"],
        capture_output=True,
        text=True,
        check=True
    )
except subprocess.CalledProcessError as e:
    print(f"Error running rpm command: {e.stderr}")
    exit(1)

# Filter lines to keep only XYZ-related packages (case-insensitive)
xyz_packages = [line.strip() for line in result.stdout.splitlines() if "xyz" in line.lower()]

Step 2: Extract Version Numbers from Package Names #

Next, we'll parse each package name to extract the version string. Using split() and rsplit() instead of awk:

version_list = []
for pkg in xyz_packages:
    # Split package name from the rest (split on first '-')
    _, version_part = pkg.split("-", 1)
    # Split off the architecture suffix (split on last '.')
    full_version = version_part.rsplit(".", 1)[0]
    version_list.append(full_version)

For your example packages like XYZman-5.3.1.9-1.x86_64, this will extract 5.3.1.9-1 as the full version string.

Step 3: Implement sort -u Behavior Natively #

To replicate sort -u (sort then deduplicate, keeping unique values in sorted order), we have a few clean options in Python:

Option 1: Use sorted() + dict.fromkeys() (Python 3.7+) #

Python 3.7+ preserves insertion order in dictionaries, so this is a concise way to get sorted unique values:

# Sort the versions first
sorted_versions = sorted(version_list)
# Deduplicate while keeping order
unique_sorted_versions = list(dict.fromkeys(sorted_versions))

Option 2: Manual Deduplication (Works for all Python 3 versions) #

If you need compatibility with older Python versions, a simple loop works well:

unique_sorted_versions = []
previous_version = None
for v in sorted(version_list):
    if v != previous_version:
        unique_sorted_versions.append(v)
        previous_version = v

Option 3: Use OrderedDict (Python 2.7 / 3.1-3.6) #

For Python versions before 3.7, OrderedDict ensures order is preserved:

from collections import OrderedDict

sorted_versions = sorted(version_list)
unique_sorted_versions = list(OrderedDict.fromkeys(sorted_versions))

Final Result #

After running these steps, unique_sorted_versions will contain your sorted, unique version numbers. For your specific case, it will be ['5.3.1.9-1'].

You can access the single unique version directly with unique_sorted_versions[0] if you're sure there's only one version present.

内容的提问来源于stack exchange，提问作者Marcos