119
AVChaining Commands - The Real Power
Linux commands become incredibly powerful when you chain them together. Each simple
command can pipe its output to the next, creating complex workflows from basic building
blocks.
Here's how to combine commands to solve real-world problems.
1. Find All Text Files
find . -type f -name "*.txt"
Search your current directory and all subdirectories for files ending in .txt. The dot means 'start
here', -type f means 'files only', and -name specifies the pattern.
2. Find and Read All Text Files
find . -type f -name "*.txt" | xargs cat
Now we pipe those filenames to xargs, which runs cat on each file. This displays all the contents
of all .txt files one after another.
3. Find Error Lines in All Text Files
find . -type f -name "*.txt" | xargs cat | grep "ERROR"
Add grep to search through all that content and show only lines containing ERROR. Great for
scanning log files to find problems.
4. Sort and Remove Duplicate Errors
find . -type f -name "*.txt" | xargs cat | grep "ERROR" | sort -k4
| uniq -f3
Now we organize the results:
● sort -k4 sorts lines by the 4th column (useful if timestamps are there)
● uniq -f3 removes duplicate lines while skipping the first 3 fields (so you see each unique
error type once)
5. Save Results to a File
find . -type f -name "*.txt" | xargs cat | grep "ERROR" | sort -k4 |
uniq -f3 > errors.log
The > symbol redirects all that output into a file called errors.log instead of showing it on screen.
Now you have a clean report of unique errors.
6. Copy Log Files to Backup Folder
find . -type f -name "*.log" -exec cp {} ./backup \;
Uses -exec to run a command on each file found. The {} gets replaced with each filename, and
\; marks the end of the command. This copies all .log files to your backup folder.
7. Backup Files with Directory Structure
find . -type f -name "*.txt" -exec rsync -R {} ./backup \;
Similar to the previous command, but rsync with -R flag preserves the directory structure. So if
you have logs/app/error.txt, it creates backup/logs/app/error.txt instead of dumping everything in
one folder.
@avdi.md
