Why "\b" doesn't work in the regex pattern of find?

Question

I'm using the find command in Mac OS X 10.9, I tried commands like this:

$ touch "a gre a"
$ find -E . -iregex ".*\bgre\b.*"

It looks that the find will not return this file named a gre a.. Does anyone have ideas about this? Thanks!

score 6 · Accepted Answer · answered Nov 13 '13 at 07:49

6

find command's regex engine (ERE) doesn't support \b for word boundaries.

On OSX following will work for word boundaries:

find -E . -iregex ".*[[:<:]]gre[[:>:]].*"

answered Nov 13 '13 at 07:49

anubhava

You mean extended (modern) regular expressions doesn't include `\b` as shorthand, or `\b` is missing only in `find`'s ERE? Do you know how I can know whether a shorthand exist in a command's regex function.. Thanks very much! – Hanfei Sun Nov 13 '13 at 07:53
1

I believe on OSX tools `\b` isn't supported in other tools like awk, sed also. I usually find online sited to looks for documentation on ERE since man paged doesn't cover it. – anubhava Nov 13 '13 at 07:57
On other systems `\<` and `\>` are supported as word boundaries but OSX (BSD) has this weird syntax `[[:<:]]` and `[[:>:]]` – anubhava Nov 13 '13 at 08:03

1 Answers1