Checking flash usage before an IOS upgrade Which command shows the files stored in flash, their sizes, and remaining free space so you can verify whether the current IOS image and a new image can coexist in flash memory?

Introduction / Context:
Before upgrading IOS, you need to ensure enough flash storage is available to hold both the existing and new images (or at least the new one). Cisco IOS provides commands to list files, sizes, and free space in flash so you can plan the upgrade path accordingly without risking an interruption or incomplete transfer.

Given Data / Assumptions:

• You want to retain the current working image during the upgrade.
• Flash is the storage medium for IOS images on the device.
• You need to confirm total and free flash capacity and file sizes.

Concept / Approach:

show flash displays flash directories, file names, sizes, and the amount of free space. This output lets you decide whether to delete old images, expand storage, or proceed with a parallel image. Although dir flash: is also commonly available, exam objectives and many platforms emphasize show flash as the canonical command.

Step-by-Step Solution:

Verification / Alternative check:

After copying the new image, run show flash again to confirm its presence and remaining free bytes. Use show version to verify the boot variable and configuration register for next reload behavior.

Why Other Options Are Wrong:

• show version reports the running image but not detailed flash utilization.
• show memory concerns RAM/processor memory, not flash storage.
• show buffers shows I/O buffer stats, unrelated to flash.
• dir flash: can work on many platforms, but the question seeks the canonical command specifically called out in many study guides: show flash.

Common Pitfalls:

• Confusing RAM (where IOS runs) with flash (where IOS is stored).
• Not verifying free space before the copy, leading to partial transfers.

Final Answer:

show flash