yes - Linux

Overview

The Linux yes command is used to repeatedly output a specific string or a default ‘y’. This simple command is primarily used for automating responses to prompts provided by other commands or scripts. It is particularly useful in situations involving repetitive tasks, such as scripting and programming, where an automatic affirmation to a continuous prompt is required.

Syntax

The usage of the yes command is straightforward:

yes [STRING]
yes [OPTION]
  • STRING specifies the string to be repeated. If no STRING is given, yes outputs ‘y’ by default.
  • OPTION includes options like --help or --version that provide additional information rather than executing the main functionality.

Options/Flags

  • --help: Display a help message and exit.
  • --version: Show version information and exit.

There are no complicated options or flags for yes. Its simplicity is one of its hallmarks.

Examples

  1. Basic Example:

    yes

    This command will continuously output ‘y’ until the process is stopped (typically with CTRL+C).

  2. Custom String:

    yes "I agree"

    Outputs ‘I agree’ repeatedly.

  3. Using with a Command:

    yes | rm -i *.txt

    This chain of commands will automatically respond with ‘y’ to all prompts that arise from deleting .txt files in the directory.

Common Issues

  • Termination: New users might not know how to stop yes, which can lead to system performance degrading if run unchecked. To terminate the command, use CTRL+C.

  • Large Outputs: When redirected to a file or another command, yes can generate large amounts of data quickly, potentially consuming significant storage space or processing power.

Integration

yes can be effectively combined with other commands to automate scripted tasks. Here’s an example with apt-get:

yes | sudo apt-get update

This use of yes auto-confirms all prompts that occur during the update process.

  • echo: Similar to yes for outputting text, but only does so once per invocation.
  • printf: Another tool for formatted output in scripts.

For further reading, visiting the official GNU coreutils page for yes can provide more technical details and updates: GNU Coreutils – yes.

This manual serves as a guide to understanding and using the yes command in various Linux environments, helping both beginners and experienced users automate and streamline operations involving repetitive user confirmation.