Yes (Unix)
Encyclopedia : Y : YE : YES : Yes (Unix)
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Purpose
Outputs an affirmative response or a string of text continuously until killed.
Syntax
yes [ STRING ] yes OPTION
Options
--helpDisplays help and exits
--versionOutputs version information and exits
Description
By itself, the yes command outputs 'y' or whatever is specified as the STRING argument (above), followed by a newline, until stopped by the user or otherwise killed; when piped into a command, it will continue until the pipe breaks (i.e., the program completes its execution).
It can also be used to test how well a system handles high loads, as using yes results in 100% processor usage, for systems with a single processor (for a multiprocessor system, a proccess must be run for each processor). This, for example, can be useful for investigating whether a system's cooling system will be effective when the processor is running at 100%.
Uses
yes can be used to send an affirmative response to any command that would otherwise request one, and thereby causing the command to run non-interactively.
(Note, this may be deprecated - the vast majority of commands that would request response from the user have either a 'force' option (e.g., 'rm -f') or an 'assume-yes' option (e.g., 'apt-get -y' in Debian).)
Example
To display the word first to the screen, type:
yes firstThis statement displays the word, once per line, until killed.
| Unix command line programs ( ) | |||
| File and file system management: | cat | chdir/cd | chmod | chown | chgrp | cp | du | df | fdupes | file | fsck | ln | ls | lsof | mkdir | more | mount | mv | pwd | rcp | rm | rmdir | split | touch | tree | ||
| Process management: | anacron | at | chroot | cron/crontab | kill | nice | ps | sleep | time | timex | top | renice | wait | ||
| User Management/Environment: | env | finger | id | locale | mesg | passwd | su | sudo | uname | uptime | w | who | write | ||
| Text processing: | awk | cut | diff | ex | head | iconv | join | less | more | nkf | paste | sed | sort | tail | tr | uniq | wc | xargs | ||
| Shell programming: | echo | expr | unset | Printing: | lp |
| Communications: inetd | netstat | ping | rlogin | traceroute | Searching: egrep | fgrep | find | grep | strings | Miscellaneous: banner | bc | cal | man | uname | wall | yes | |
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