[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

bug#20443: grep pattern is forward slash + star

From: Eric Blake
Subject: bug#20443: grep pattern is forward slash + star
Date: Mon, 27 Apr 2015 14:53:02 -0600
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0

tag 20443 notabug

On 04/27/2015 01:05 PM, Clay Hansen wrote:
> Dear Coders,
> if I echo 'a  *  z' | grep '/*' it succeeds and prints 'a  *  z'.
> Can this be right?

Yes.  The regular expression '/*' says to match 0-or-more instances of
'/'. 'a  *  z' has zero instances of '/', so it matches and gets printed.

> echo 'a  *  z' | grep -F '/*' fails as expected.

That's the literal pattern '/*', which does not appear in your input.

Remember, to convert the literal pattern of '/*' under -F to a regular
expression when not using -F, you must escape any characters that are
otherwise special to regular expressions.  Your second command would be
equivalent to:

echo 'a  *  z' | grep '/\*'

where the '*' now matches a literal star rather than being the

As such, this is not a bug, so I'm closing the report.  However, feel
free to ask further questions on the topic.

Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

Attachment: signature.asc
Description: OpenPGP digital signature

reply via email to

[Prev in Thread] Current Thread [Next in Thread]