Hosting Operations

Read-only, can be slow

Compare Source and Backup File Lists

You need to compare relative file paths in source and backup directories.

Command

comm -3 <(find source -type f | sed 's#^source/##' | sort) <(find backup -type f | sed 's#^backup/##' | sort)

Before you run this

System impact: Read-only. Can create load on large logs, directories, filesystems, or process tables.

When not to use it: Do not use it to prove files have identical contents; compare checksums or use rsync itemization too.

Expected output

Paths present only on one side of the comparison.

System impact

Read-only, can be slow. Nothing changes. The command compares sorted relative file lists.

Scope this to the smallest useful path or service on busy systems.

Recovery / rollback: no state is changed.

When to use it

Use when checking whether a backup contains the same files as the source tree.

When not to use it

Do not use it to prove files have identical contents; compare checksums or use rsync itemization too.

Watch this command run

Command transcript

This sanitized transcript shows the commands and output shape without exposing host details.

demo@lab:~$

$ find source backup -type f | sort

backup/.snapshot
backup/app/config.yml
backup/content/index.md
backup/old-report.csv
backup/tmp/empty.cache
source/app/config.yml
source/assets/logo.svg
source/content/about.md
source/content/index.md

$ comm -3 <(find source -type f | sed 's#^source/##' | sort) <(find backup -type f | sed 's#^backup/##' | sort)

	.snapshot
assets/logo.svg
content/about.md
	old-report.csv
	tmp/empty.cache

View commands shown

These are the commands shown in the sanitized transcript.

Commands shown

find source backup -type f | sort
comm -3 <(find source -type f | sed 's#^source/##' | sort) <(find backup -type f | sed 's#^backup/##' | sort)

next steps

Related commands

Hosting Operations Deletes data

Check Required Files After Restore

A successful extraction still needs a required-file check.

cd restore-dr && rm -rf restore-sandbox/full && mkdir -p restore-sandbox/full && tar -xf backups/2026-06-25/site.tar -C restore-sandbox/full && find restore-sandbox/full -type f | sed 's#^restore-sandbox/full/##' | sort | comm -23 required-files.txt -

Hosting Operations Can be slow

Find Files Newer Than a Backup Snapshot

Files newer than the last snapshot are the ones most likely missing from it.

find source -type f -newer backup/.snapshot -print | sort

Hosting Operations Read-only

Find Missing Files in an Old Backup

The fastest failed restore drill is the one that finds missing critical files early.

cd restore-dr && tar -tf backups/2026-06-24/site.tar | sed 's#^./##' | sort | comm -23 required-files.txt -

Hosting Operations Can be slow

List Newest Source Files Before Backup

Before trusting a backup, know which files changed most recently.

find source -type f -printf '%TY-%Tm-%Td %TH:%TM %p\n' | sort

Hosting Operations Can be slow

List Largest Files in a Backup

Large backup files are where storage surprises usually start.

find backup -type f -printf '%s %p\n' | sort -nr | head

Study mapping

Use this as independent command practice: read the notes, predict the output, then compare it with the example before using a real shell.

Compare Source and Backup File Lists

Before you run this

Expected output

System impact

When to use it

When not to use it

Command transcript

Commands shown

Related commands

Check Required Files After Restore

Find Files Newer Than a Backup Snapshot

Find Missing Files in an Old Backup

List Newest Source Files Before Backup

List Largest Files in a Backup

Useful for