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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.

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.

BACKUP_ROOT=/srv/backups/site && tar -tf "$BACKUP_ROOT/2026-06-25/site.tar" | sed 's#^./##' | sort
Linux Survival Basics Can be slow

Count Failures by Test File

Turn noisy test logs into a ranked failure list.

grep -RhoE '[A-Za-z0-9_./-]+\.(test|spec)\.(js|ts|py|rb)' logs/ | sort | uniq -c | sort -nr | head
Linux Survival Basics Read-only

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
Linux Survival Basics Can be slow

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
Linux Survival Basics Can be slow

Show Big Files in Human Units

Byte counts are precise. Human units are faster under pressure.

find /var -type f -printf '%s %p\n' | sort -nr | head -10 | awk '{printf "%.1f MB %s\n", $1/1024/1024, $2}'
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.

  • LPIC-1 style command-line practice
  • LFCS style performance-task practice
  • Linux+ style troubleshooting review

Independent study support only. No affiliation, endorsement, exam dumps, or real exam questions.