Intro To 'yes' Command In Linux

2023-05-08 - By Robert Elder

     I use the 'yes' command like this:

yes

     which prints the letter 'y' as fast as possible:

y
y
y
y
y
...

     You can exit the 'yes' command by pressing the control and 'c' key together.

     The purpose of this command is to spam the letter 'y' as fast as possible as a way of answering 'yes' to applications that ask for confirmation.  For example, this is a file that doesn't have the write permission set for the user:

ls -l main.c

4 -r--rw-r-- 1 robert robert 46 May  8 10:31 main.c

     If I try to delete it, I'll get a confirmation prompt asking for input.

rm main.c

rm: remove write-protected regular file 'main.c'?

     If I run the 'yes' command and pipe its output into the 'rm' command, the file will be deleted without asking first:

yes | rm main.c

ls -l

total 0

     This behavior is particularly useful for writing automated scripts that need to run without human intervention:

#!/bin/bash

#  Deletes file automatically without prompt
yes | rm main.c

     In the case of using a pipe with the 'yes' command, the 'yes' command knows to exit automatically once it receives the SIGPIPE signal.  You can read more information about this concept in the following 'man' page:

man 7 signal

     Another application of the 'yes' command is to trigger high CPU load for testing purposes:

     And that's why the 'yes' command is my favourite Linux command.