Level 3 recap
⏱ Est. ~5 min
01 · Read
Level 3 done! You've learned to read, write, search, and chain commands together. Let's test what you remember about this file-contents toolkit.
💡 Picture thisYou now have a full toolkit for "working with file contents" — reading glasses (cat, head, tail), pens for writing (echo, >, >>), a magnifying glass (grep), and production-line connectors (|). Let's see if you can pick the right tool for the job.
Key points
- Read: cat for the whole file, head/tail for previews
- Write: > to overwrite, >> to append, echo to produce text
- Find: grep for patterns, -i to ignore case, -r to search recursively
- Chain: | sends one command's output into another
02 · Match
Match each command to what it does.
(This section is interactive — please enable JavaScript.)
03 · Quiz
What's the key difference between > and >>?
- > is faster than >>
- > replaces the whole file; >> adds to the end
- >> only works on text files
- > creates files; >> doesn't
04 · Fill in the blank
To find 'TODO' in every file across all subfolders, you would type: grep ___ "TODO" .
05 · Drag to sort
Sort each tool by its main purpose.
(This section is interactive — please enable JavaScript.)
06 · Quiz
Which pipeline counts the number of 'ERROR' lines in server.log?
- cat server.log | count ERROR
- wc -l server.log | grep ERROR
- grep ERROR server.log | wc -l
- find ERROR server.log | wc
Other lessons in this chapter
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