tee
Overview
tee copies stdin to stdout and to files — a T-junction in pipelines. Essential when you want to log and still process a stream.
Syntax
tee [options] [file...]Common Options
| Option | Description |
|---|---|
-a |
Append |
-i |
Ignore SIGINT |
-p |
Diagnose write errors to pipes (GNU) |
Examples with Explanations
make 2>&1 | tee build.log
echo hello | tee file.txt
echo more | tee -a file.txt
command | tee /dev/tty | wc -l
command | tee out1.txt out2.txt
sudo tee /etc/myapp.conf >/dev/null <<'EOF'
key=value
EOFWhy sudo tee?
Redirection > runs as your shell (unprivileged). sudo tee writes the file as root while you keep the pipeline.