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Linux Survival Basics

Read-only, can be slow

Count Source Files by Extension

You need a small inventory of source file types.

Command

find source -type f -printf '%f\n' | sed -n 's/.*\.//p' | sort | uniq -c | sort -nr

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 for extensionless files unless you adapt the command.

Expected output

File extension counts sorted from most common to least common.

System impact

Read-only, can be slow. Nothing changes. The command derives extensions from filenames and counts them.

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

Recovery / rollback: no state is changed.

When to use it

Use during backup sanity checks when a content type may be missing.

When not to use it

Do not use it for extensionless files unless you adapt the command.

Explanation-only example

Illustrated output, not a live lab run

This example is intentionally illustrative. It shows the command shape without killing real processes or changing your machine.

demo@lab:~$

$ find source -type f -printf '%f\n' | sort

about.md
config.yml
index.md
logo.svg

$ find source -type f -printf '%f\n' | sed -n 's/.*\.//p' | sort | uniq -c | sort -nr

      2 md
      1 yml
      1 svg
View commands shown

These are the commands shown in the sanitized transcript.

Commands shown

  1. find source -type f -printf '%f\n' | sort
  2. find source -type f -printf '%f\n' | sed -n 's/.*\.//p' | sort | uniq -c | sort -nr

next steps

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find /var -type f -printf '%s %p\n' | sort -nr | head -20
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find logs/ -type f -printf '%s %p\n' | sort -nr | head -10
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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
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Find Directories Burning Inodes

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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.

  • lpic1:103-gnu-unix-commands
  • lpic1:104-filesystems-permissions-fhs
  • lfcs:essential-commands
  • lfcs:storage
  • linuxplus:automation-scripting
  • linuxplus:provisional
  • linuxplus:system-management
  • risk:read-only

Useful for

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

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