yes

yes will continuously output lines with y until user uses ctrl+c to stop. yes Can be useful for automating scripts.

$ yes
y
y
^C
$ yes n
n
n
n
^C

Useful Options / Examples

yes | rm -i *.txt

$ls -l *txt
-rw-r--r--  1 apple  staff  0 Mar 25 00:54 1.txt
-rw-r--r--  1 apple  staff  0 Mar 25 00:54 2.txt
-rw-r--r--  1 apple  staff  0 Mar 25 00:54 3.txt
$yes | rm -i *.txt
remove 1.txt? remove 2.txt? remove 3.txt? %

Break it down

• Pipe yes to the following command to automatically make the following command prove any raised question with form [y/n].

• When using rm -i to delete normal files, the system will ask user for confirmation of removing the file. At this time, the yes command will be able to simplify the process of repeatedly typing in yes. Here yes | rm -i *.txt will continuously pipe yes to the command rm -i to confirm the deleting operation.

yes [text] > [filename]

#!/bin/sh  
  
yes hello >hello.txt &  
PID=$!  
  
sleep 1  
kill $PID 

Break it down

• The yes command is convenient to generate repeated text. We can use it in shell script like above to generate a file with repeated string hello. Here we run the yes hello for 1 second to generate large number of hello. We can also use yes hello | head 1000 to generate hello 1000 times.