Linux Shell Scripting Cookbook - Third Edition

Count modifiers

An Identifier may occur once, never, or many times. The Count Modifier defines how many times a pattern may appear.

regex	Description	Example
?	This means that the preceding item must match one or zero times	colou?r matches color or colour, but not colouur
+	This means that the preceding item must match one or more times	Rollno-9+ matches Rollno-99 and Rollno-9, but not Rollno-
*	This means that the preceding item must match zero or more times	co*l matches cl, col, and coool
{n}	This means that the preceding item must match n times	[0-9]{3} matches any three-digit number; [0-9]{3} can be expanded as [0-9][0-9][0-9]
{n,}	This specifies the minimum number of times the preceding ...