yes Command
Beginner Shell Scripting man(1)Output a string repeatedly until killed
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📅 Updated: Mar 15, 2026
SYNTAX
yes [STRING]
What Does yes Do?
yes outputs a string repeatedly until killed. Without arguments, it outputs "y" endlessly. With an argument, it outputs that string repeatedly. yes is primarily used to automatically answer confirmation prompts in scripts.
yes generates output as fast as possible, making it also useful for stress testing, generating test data, and filling pipes. It is a simple but essential automation tool.
In modern scripting, many commands offer -y or --yes flags for non-interactive confirmation, reducing the need for yes. But it remains useful for commands without such flags.
yes generates output as fast as possible, making it also useful for stress testing, generating test data, and filling pipes. It is a simple but essential automation tool.
In modern scripting, many commands offer -y or --yes flags for non-interactive confirmation, reducing the need for yes. But it remains useful for commands without such flags.
Options & Flags
| Option | Description | Example |
|---|---|---|
| (no args) | Output "y" repeatedly | yes | head -5 |
| STRING | Output STRING repeatedly | yes "I agree" | head -3 |
| piped | Auto-answer prompts | yes | apt install package |
Practical Examples
#1 Auto-confirm prompts
Automatically answers "y" to each rm confirmation prompt.
$ yes | rm -i *.tmp#2 Custom string
Outputs "I accept" three times.
$ yes "I accept" | head -3
Output:
I accept
I accept
I accept
#3 Auto-accept license
Automatically accepts all prompts during installation.
$ yes | ./installer.sh#4 Generate test lines
Creates a 1000-line test file.
$ yes "test data" | head -1000 > testfile.txt#5 Answer no
Automatically answers "n" to all prompts.
$ yes n | dangerous-command#6 Fill disk (testing)
Creates a 100MB test file filled with "y\n" characters.
$ yes | dd of=testfile bs=1M count=100Tips & Best Practices
Use command flags instead: Many commands have -y or --yes flags: apt install -y, rm -f. These are cleaner than piping yes.
yes is very fast: yes outputs gigabytes per second. Always pipe to a command or limit with head to avoid filling disk/memory.
Can cause damage: yes | dangerous_command will answer y to ALL prompts without discrimination. Make sure you want to confirm everything.
Frequently Asked Questions
What does yes do?
yes outputs "y" (or a specified string) repeatedly until killed. It is used to automatically answer confirmation prompts in scripts.
How do I auto-confirm command prompts?
Pipe yes: yes | command. Or better, use the command's own flag: apt install -y, rm -f.
How do I stop yes?
Press Ctrl+C, or pipe it to a command that will close stdin when done: yes | head -10.
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