tee

tee is a command-line utility used to read from standard input and write to standard output and files simultaneously. It is commonly used in pipelines to capture intermediate output.

Basic Syntax

tee [options] [file...]

Commonly Used Options

-a, --append: Append to the given files, do not overwrite.
-i, --ignore-interrupts: Ignore interrupt signals.
--output-error[=mode]: Adjust behavior on write errors. Modes include warn, warn-nopipe, and exit.

Examples

Basic Usage

Write the output of a command to a file and display it on the terminal:

echo "Hello, World!" | tee output.txt

Append to a File

Append the output of a command to a file:

echo "Additional line" | tee -a output.txt

Use with Pipelines

Capture the output of a command in a file while passing it to another command:

ls -l | tee filelist.txt | grep ".txt"

Ignore Interrupts

Ignore interrupt signals while writing to a file:

echo "This will ignore interrupts" | tee -i output.txt

Multiple Files

Write the output to multiple files:

echo "Hello, multiple files!" | tee file1.txt file2.txt

Handle Write Errors

Adjust behavior on write errors:

echo "Handle write errors" | tee --output-error=warn output.txt

Conclusion

tee is a versatile tool for duplicating the output of a command to both standard output and files. Understanding its options allows for efficient and powerful output management in command-line operations.

Last modified: 14 December 2024