Foundation project
Project: summarize a log file
Lesson 11 of 20 · 15 min · Module 3: Text superpowers
Turn a raw log into a small report a teammate can read in seconds. This project combines folders, search, counting, and redirection.
Start this lesson →Free. No installation: you write and run the code in your browser, and it is checked automatically.
By the end, you’ll be able to…
- Plan a report as a sequence of commands
- Write counts and lines into files
- Combine overwrite and append correctly
The idea
Real reports are built from small commands. Each command writes or appends one piece of the result to a file.
mkdir -p reports
grep WARN logs/app.log > reports/warnings.txt01Plan the output first
Write down what each file must contain before you type. Then pick one command per piece: grep for lines, grep -c for counts, echo for fixed text.
02Build a file in steps
The summary starts with > (a fresh file with the title) and continues with >> (the count added under it). The order of these two commands matters.
echo "app.log report" > reports/summary.txt
grep -c ERROR logs/app.log >> reports/summary.txt
cat reports/summary.txtapp.log report
303Check what you made
Finish with cat on each file. Reading your own output is how professionals catch a > that should have been >>.
Your project brief
reports folder in your home folder and fill it with three files:1)
reports/errors.txt: every line of logs/app.log that contains ERROR (uppercase only).2)
reports/warn-count.txt: the number of lines that contain WARN.3)
reports/summary.txt: the line app.log report, followed by a line with the number of ERROR lines.What the checks look for
- errors.txt contains exactly the 3 uppercase ERROR lines
- warn-count.txt contains 2
- summary.txt has the title and the error count
- Uses grep to build the report
Take this with you
A report is a few small, checked commands writing to well-named files.
Go a little further
Add a fourth file listing the distinct ERROR messages with their counts.