A string constant is a sequence of zero or more characters enclosed in double quotation marks. A string constant can be of any length, and they can have any of the possible 8-bit ASCII characters. These string constants can be stored in variables or appear literally as string constants, such as "River" or " ".
For example, if we want to print those records from cars.dat that contain the maruti string in the first field, we have to enclose the maruti string in double quotes while performing the match as follows:
$ awk '$1 == "maruti" {print}' cars.dat
The output of the execution of the preceding code is as follows:
maruti swift 2007 50000 5
maruti dezire 2009 3100 6
maruti swift 2009 4100 5
maruti esteem 1997 98000 ...