Belkasoft X Help Contents

Regular expression syntax

Below is the table of the most commonly used characters, with their meanings and examples.

Regular expression Explanation Example Matching
. Any single character excluding a newline .ar The car parked in the garage
[ ] Searches for any of the characters in parentheses. [Tt]he The car parked in the garage
[a-z] A dash means a range of characters [e-g] The seller sold 2 guns and 7 pistols.
[0-9] Finds any digit between 0 and 9 [3-8] The seller sold 2 guns and 7 pistols.
[^ ] Matches any character that is not contained between the square brackets [^c]ar The car parked in the garage.
\. A dot matches almost any character, use \ symbol to find a regular dot ar\. A garage is a good place to park a car.
| The pipe symbol "|" acts as an OR operator gr[e|a]y grey, gray
{m} Repeat exactly m times colou{3}r colouuur
{m,n} Repeat from m to n times colou{2,4}r colouur, colouuur, colouuuur
{m,} Repeat at least m times colou{2,}r colouur, colouuur, colouuuur, etc.
{,n} Repeat not less n times colou{,3}r color, colour, colouur, colouuur
? Makes the preceding character optional. Matches zero or one times: corresponding {0,1} colou?r color, colour
* Repeat zero-or-more times: corresponding {0,} colou*r color, colour, colouur, etc.
+ Repeat once or more times: corresponding {1,} colou+r colour, colouur, etc (but not color)
^ Finds the beginning of the entered string ^a aaa aaa
x$ A line ending with the x a$ aaa aaa
(xyz) Finds a group of characters in a strictly specified order. (at) Fat cat is going to Staten Island
\ Cancel the special meaning of the metacharacter that follows it. Allows searching for service characters [] () {}. * +? ^ $ \ | (f|c|m)at\.? The fat cat sat on the mat.
\s Space \s*cat\s* The fat cat sat on the concatenation.
/^Yes/ A line starting with Yes /^Yes/ Yes ... Yesterday ...
/th/ Occurrence of the string th anywhere in a word /th/ the, there, path, bathing, etc.

Example: how to find artifacts like 123-1234 with any number? Use this regular expression: [0-9]{3}-[0-9]{4}.