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Comment by mooktakim | Hacker News Reader

If anyone, like me, is wondering what "yes" is used for. You can use to pipe "y" to commands that require interactivity, so if you just want to say "y" to all the inputs, you can use "yes" to do this:

  yes | rm -r large_directory

  yes | fsck /dev/foo

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On my quad-core MacBook, I've used "yes" in four different terminals as a way to quickly test a 100% CPU load.

Yes (so to speak), you can also do 'yes &' multiple times to create lots of background load (and then 'pkill yes' before anything melts...)

I know its only an example but why

   yes | rm -r <>

and not

    rm -rf <>

I believe "yes" has become less useful over the years, with flags like force and quiet solves this now.

I think rm -rf would also suppress errors in addition to confirmation messages, so presumably if you want a "soft" force...

No it doesn't.

  > rm -rf foo/bar
  rm: foo/bar: Permission denied

If foo/bar does not exist, it should be silent. Via http://pubs.opengroup.org/onlinepubs/007904975/utilities/rm.... on the -f option:

> [...] Do not write diagnostic messages or modify the exit status in the case of nonexistent operands. [...]

Yes, but that's the only error it suppresses, and that's because "not existing" isn't really an error for a tool that's trying to delete something. In my example foo/bar existed but I didn't have permissions to delete it, and as you'll see it printed out that error.

I sometimes do

   yes "" | cat -n

to generate a sequence number.

Try `seq 1 n`

euske may be using one of the operating systems (one such being mentioned on this very page) where there is no seq utility.

    JdeBP ~ $seq
    ksh: seq: not found
    JdeBP ~ $

Of course, on the one mentioned there is jot.

And on bash you can simply use {1..n}:

    $ echo {1..5}
    1 2 3 4 5

If you have Bash 4.0 or above, you can include a step size:

    $ echo {1..10..2}
    1 3 5 7 9

"yes d | mail" is an excellent way to get rid of failed cron job mails.

Why wouldn't it be `mail | yes d` if you're trying to answer "d" to all of the input requests of mail?

Because you want all the d's to be sent to mail...

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