Notes from this - April 2018 - YouTube video:
OnCommand Insight Device Resolution 102 - Regular
Expressions
Image: Zone regular expression: Type = Host: Source =
Zone: Method = Regular Expression
‘Zone regular expression’ also shows:
- All regular expressions for this auto resolution
rule
- Order of precedence for regular expressions
- Number of matches with each additional expression
A Note on Regular
Expressions
- A regular expression, often called a pattern, is an
expression used to specify a set of strings required for a particular purpose.
- Regular expressions can be very broad - such as
using (.*) which grabs the entire alias string - or can be create to
capture one specific alias string.
Basics
- The () (parentheses) indicate the characters
that are being extracted for device name.
- The . (period) is a wildcard that matches any
character.
- The * (asterisk) matches the preceding
character, or preceding bracketed characters, 0 or more times:
--- Example: tre* will find tree, tread
and trough.
- The + (plus) matches the previous character 1 or
more times:
--- Example: tre+ will find tree and tread
but not trough.
- The ? (question mark) matches the preceding
character 0 or 1 time only:
--- Example: colou?r will find both color
and colour.
Example #1
Zone name: S0422_myComputer1Name_HBA3
Regular expression: S[0-9]+_([a-zA-Z0-9]+)[_-]HBA[0-9]
Explanation:
-
Match everything starting with “S”
- One or
more numbers
- A “_”
-
A set of characters or numbers
- A “_”
or “-“
- “HBA”
-
With a single number
- Return what was matched in the first parenthesis (this
is the meaning of \1)
Example #2
Zone name: myComputerName123_HBA1_Symm1_FA1
Regular expression: ([a-zA-Z0-9]+)_.*
Explanation:
-
Return a set of all characters and numbers that appear in the zone name
before the “_”
- Match “_”
- And ‘.*’
anything after
Example #3
Zone name: MyComputerName_HBA1_Symm1_FA1
Regular expression: (.*?)_.*
Explanation:
- This regular expression will simply find anything
before the first “_”
- “.*” is greedy and could grab everything up to the last
“_” but the “?” says stop at the first
Example #4
Zone names: Z1_APPLE43A_FCAW0_SYMM_FA4A, Z2_BANANA44B_LPFC0_SYMM_FA4A,
Z3_PEAR45C_FCAW0_SYMM_FA13A
Regular expression: .*?_([a-zA-Z0-9]+)_.*
Explanation:
- .*?
will grab everything up to the first “_”
- ([a-zA-Z0-9]+)
will grab everything to the second “_”
Enter Regular
Expression
“\1” format indicates which set of parentheses we
are extracting device name from.
Image: NetApp OCI Enter Regular Expression
Best Practice: Set Auto resolution schedule to ‘Every Day’
at midnight.
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