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Top Forums Shell Programming and Scripting Delete all lines starting with # character Post 303002532 by durden_tyler on Saturday 26th of August 2017 05:40:27 PM
Old 08-26-2017
Quote:
Originally Posted by John K
...
Where can I read more about "\s" ? What is this operator called ? (So that I can google about it )
It's a "metacharacter" or a "shorthand character class" in a regular expression.
Any book, blog or webpage on regular expressions should mention it.

Here's the Wikipedia page on regular expressions; search for "\s" on that page:
Regular expression - Wikipedia

Here's Jan Goyvaert's website on regular expressions in general. Pretty decent stuff.
Regexp Tutorial - Shorthand Character Classes

In particular, if you are looking for using regular expressions in the Vim editor, then this page looks pretty good:

Vim Regular Expressions 101

The books mentioned at the bottom of the above page are good too.
Jeffrey Friedl's book on regular expressions is the most advanced and a gold mine of information.
These 2 Users Gave Thanks to durden_tyler For This Post:
 

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REGEXP(6)							   Games Manual 							 REGEXP(6)

NAME
regexp - regular expression notation DESCRIPTION
A regular expression specifies a set of strings of characters. A member of this set of strings is said to be matched by the regular expression. In many applications a delimiter character, commonly bounds a regular expression. In the following specification for regular expressions the word `character' means any character (rune) but newline. The syntax for a regular expression e0 is e3: literal | charclass | '.' | '^' | '$' | '(' e0 ')' e2: e3 | e2 REP REP: '*' | '+' | '?' e1: e2 | e1 e2 e0: e1 | e0 '|' e1 A literal is any non-metacharacter, or a metacharacter (one of .*+?[]()|^$), or the delimiter preceded by A charclass is a nonempty string s bracketed [s] (or [^s]); it matches any character in (or not in) s. A negated character class never matches newline. A substring a-b, with a and b in ascending order, stands for the inclusive range of characters between a and b. In s, the metacharacters an initial and the regular expression delimiter must be preceded by a other metacharacters have no special meaning and may appear unescaped. A matches any character. A matches the beginning of a line; matches the end of the line. The REP operators match zero or more (*), one or more (+), zero or one (?), instances respectively of the preceding regular expression e2. A concatenated regular expression, e1e2, matches a match to e1 followed by a match to e2. An alternative regular expression, e0|e1, matches either a match to e0 or a match to e1. A match to any part of a regular expression extends as far as possible without preventing a match to the remainder of the regular expres- sion. SEE ALSO
awk(1), ed(1), sam(1), sed(1), regexp(2) REGEXP(6)
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