$ Linux One Liners
Back to lessons

Linux Survival Basics

Count Failures by Test File

A CI log has repeated failures and you need to see which files appear most often.

Command

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

What changed

Nothing changes. The command extracts and counts file path mentions.

Danger

safe

When to use it

Use when a test suite produces many repeated failure lines.

When not to use it

Do not use it when your CI emits structured JSON test reports that should be queried directly.

Undo or recovery

No undo needed because this command is read-only.

Expected output

A ranked list of test file paths with occurrence counts.

demo script

Disposable terminal steps

  1. cat logs/test.log
  2. grep -RhoE '[A-Za-z0-9_./-]+\.(test|spec)\.(js|ts|py|rb)' logs/ | sort | uniq -c | sort -nr | head
Terminal transcript Demo JSON

simulated output

What it looks like

disposable vessel 
::fixture-ready::
$ cat logs/test.log
fail tests/checkout.spec.ts
fail tests/login.spec.ts
fail tests/checkout.spec.ts
::exit-code::0
$ grep -RhoE '[A-Za-z0-9_./-]+\.(test|spec)\.(js|ts|py|rb)' logs/ | sort | uniq -c | sort -nr | head
      2 tests/checkout.spec.ts
      1 tests/login.spec.ts
      1 checkout.spec.ts
::exit-code::0

YouTube Short

Rank failing tests.

Extract test filenames from the log, count them, and sort. Now the noisy failure has a shape.

LinkedIn hook

Turn noisy test logs into a ranked failure list.

Question: When many tests fail, do you rank the failures or inspect them in log order?

experiments

A/B tests to run

Metric: retention_rate

A: Rank failing tests.

B: Give noisy CI a shape.