# a question about RE

**URL:** https://community.zeek.org/t/a-question-about-re/450
**Category:** Zeek
**Created:** [January 17, 2004, 6:56am UTC](https://community.zeek.org/t/a-question-about-re/450 "2004-01-17T06:56:34Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![user32](https://avatars.discourse-cdn.com/v4/letter/u/43a26b/32.png) [@user32](https://community.zeek.org/u/user32)
#### Post date: [January 17, 2004, 6:56am UTC](https://community.zeek.org/t/a-question-about-re/450/1 "2004-01-17T06:56:34Z")

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hello everyone£¡

I have a question about a regular-expression line in "scan.l" file.  
It is:  
ESCSEQ (\\([^\n]|[0-7]+|x[[:xdigit:]]+))

I can't understand what "[[:xdigit:]]" means?  
Would you give me an explanation?

Thanks & Regards!

herdsman sun  
Netpower Inc. in Beijing

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### Author: ![system](https://canada1.discourse-cdn.com/flex011/uploads/zeek/original/1X/f09d732bc2cc7c7cc7e35db67cf4e1d5233ce7a7.png) [@system](https://community.zeek.org/u/system)
#### Post date: [May 6, 2022, 3:36pm UTC](https://community.zeek.org/t/a-question-about-re/450/2 "2022-05-06T15:36:54Z")

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