Linux Survival Basics

Read-only

List Contents of a Backup Tarball

You need to see what a backup tarball contains before restoring it.

Command

tar -tf archives/site-backup.tar | sort | head

Before you run this

System impact: Read-only. Low when scoped to the shown target.

When not to use it: Do not treat a file listing as content verification; pair it with checksums when possible.

Expected output

A sorted sample of paths stored inside the tar archive.

System impact

Read-only. Nothing changes. The command lists archive member names.

Recovery / rollback: no state is changed.

When to use it

Use before extracting a backup archive or when checking whether expected files are present.

When not to use it

Do not treat a file listing as content verification; pair it with checksums when possible.

Watch this command run

Command transcript

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

demo@lab:~$

$ ls -lh archives/site-backup.tar

-rw-r--r-- 1 root root 10K Jun 26 00:27 archives/site-backup.tar

$ tar -tf archives/site-backup.tar | sort | head

./
./app/
./app/config.yml
./assets/
./assets/logo.svg
./content/
./content/about.md
./content/index.md

View commands shown

These are the commands shown in the sanitized transcript.

Commands shown

ls -lh archives/site-backup.tar
tar -tf archives/site-backup.tar | sort | head

next steps

Related commands

Hosting Operations Read-only

List Archive Contents Before Extracting

You can inspect a tar backup before it writes a single file.

cd restore-dr && tar -tf backups/2026-06-25/site.tar | sed 's#^./##' | sort

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Count Failures by Test File

Turn noisy test logs into a ranked failure list.

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Find the Largest Installed Packages

Disk cleanup starts with evidence, not random package removal.

dpkg-query -W -f='${Installed-Size}\t${Package}\n' | sort -nr | head -20

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Find the Files Eating Your Disk

The disk was full, but guessing at folders was the slow part.

find /var -type f -printf '%s %p\n' | sort -nr | head -20

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Find the Processes Using Memory

The server felt slow. Memory pressure was the first thing to rule out.

ps -eo pid,comm,%mem,%cpu --sort=-%mem | 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.

List Contents of a Backup Tarball

Before you run this

Expected output

System impact

When to use it

When not to use it

Command transcript

Commands shown

Related commands

List Archive Contents Before Extracting

Count Failures by Test File

Find the Largest Installed Packages

Find the Files Eating Your Disk

Find the Processes Using Memory

Useful for