Regular Expressions

Regular expressions define patterns that can be used to determine whether certain sequences of characters occur within a text.

In UltraSearch, regular expressions can be used to search for files and folders whose names match a specific pattern.

To perform a search using a regular expression, place a tilde ~ in front of your search term. For example, entering ~a|b will find all files and folders whose names contain either “a” or “b”.

The following table shows some of the most used syntax and provides a few examples:

Expression

Syntax

Description

Example

Any character

 
.

Matches any single character except a line break.

a.o matches “aro” in “around” and “abo” in “about” but not “acro” in “across”.

Zero or more

 
*

Matches zero or more occurrences of the preceding expression, and makes all possible matches.

a*b matches “b” in “bat” and “ab” in “about”. e.*e matches the word “enterprise”.

One or more

 
+

Matches at least one occurrence of the preceding expression.

ac+ matches words that contain the letter “a” and at least one instance of “c”, such as “race”, and “ace”. a.+s matches the word “access”.

Start of string

 
^

Matches the start of a string

^[0-9] matches strings that start with a digit.

End of string

 
$

Matches the end of a string

exe$ matches strings that end with “exe”.

Beginning of word

 
[[:<:]]

Matches only when a word starts at this point in the text.

[[:<:]]in matches words such as “inside” and “into” that begin with the letters “in”.

End of word

 
[[:>:]]

Matches only when a word ends at this point in the text.

ss[[:>:]] matches words such as “across” and “loss” that end with the letters “ss”.

Any one character in the set

 
[]

Matches any one of the characters in the []. To specify a range of characters, list the starting and ending characters separated by a dash (-), as in [a-z].

be[n-t] matches “bet” in “between”, “ben” in “beneath”, and “bes” in “beside” but not “bel” in “below”.

Any one character not in the set

 
[^...]

Matches any character that is not in the set of characters that follows the ^.

be[^n-t] matches “bef” in “before”, “beh” in “behind”, and “bel” in “below”, but not “ben” in “beneath”.

Or

 
|

Matches either the expression before or the one after the OR symbol (|). Mostly used in a group.

(sponge|mud) matches “sponge bath” and “mud bath.

Escape character

 
\

Matches the character that follows the backslash () as a literal. This lets you find the characters that are used in regular expression notation, such as { and ^.

\^ searches for the ^ character.

Repeat n times

 
{n}

Matches n occurrences of the preceding expression.

[0-9]{4} matches any 4-digit sequence.

Grouping

 
()

Lets you group a set of expressions together. If you want to search for two different expressions in a single search, you can use the Grouping expression to combine them.

If you want to search for [a-z][1-3] or [0-9][a-z], you would combine them: ([a-z][1-3])|([0-9][a-z]).

More examples:

Regular Expression

Use Case

 
[0-9]

\d

Find all files/folders with at least one digit in its name.

 
a|b

Find all files/folders containing “a” or “b” in their name.

 
[^(A-Za-z)]

Find all files/folders containing at least one character in their name that is not in the range A-Z or a-z.

 
^E[0-9]{7}$

Find all files/folders which start with an “E” followed by exactly 7 digits.

 
[A-Za-z]:\\([^\\]+\\){2,4}[^\\]+$

Find all files/folders with a folder depth of at least 2 and at most 4.

 
[^\x00-\x7F]

Find all files/folders with invalid ASCII characters.

 
[^\P{C}]

Find all files/folders with Unicode characters which cannot be printed.

 
[\xA0]

Find all file/Folder names that contain the non-breakable space character (Unicode NOBR, U+00A0) instead of a normal space character.

 
[~"#%&*:<>?\/\\{|}]

Find all file and folder names, that contain characters which are invalid on SharePoint servers.

 
^\s+.*

Find all files and folders with a leading space.

 
\s+(\.[^.]+)$

Find files with an extension that have a trailing space at the end of their name.

 
.*\s+$

Find folders with a trailing space at the end of their name

Further information and additional examples can be found here.

A description of all special characters that can be used with regular expression can be found here .

The following tools can assist in forming regular expressions: