Tell me more about modifiers
 
The backslash not only turns meta-characters into literal characters, it is also used to give otherwise literal characters special meaning. In the Perl-compatible regular expressions supported by Observer, this includes modifiers or controls that affect the way the entire expression is interpreted. For example, regular expressions are case-sensitive unless you use the /i modifier:
/network instruments/i
Would match:
Network Instruments and NETWORK INSTRUMENTS and Network instruments
Table 14 lists the modifiers supported by Observer’s regular expression filters. For more comprehensive definitions of all the meta-characters supported by Perl-compatible regular expressions, see http://perldoc.perl.org/perlre.html.
Table 14. Modifiers
Modifier
Description
i
Make the search case insensitive.
s
Interpret the period (.) meta-character to include newlines.
m
By default, the string is treated as one big line of characters. ˆ and $ (two other meta-characters) match at the beginning and ending of the string. When \m is set, ˆ and $ match immediately following or immediately before any newline in the buffer, as well as the very start and very end of the buffer.
x
Whitespace data characters in the pattern are ignored unless escaped or inside a character class. This is useful for making long regular expressions more readable.
A
The pattern must match only at the start of the buffer (same as ˆ)
E
Set $ to match only after the subject string. Without E, $ also matches immediately before the final character if it is a newline (but not before any other newlines).
G
Inverts the greediness of the quantifiers so that they are not greedy by default, but become greedy if followed by a question mark (?). Greediness refers to how many characters it will consider when trying to match strings of variable length.