Learning AWK Programming

The substr (str, start, [ length ]) function

The substr (str,start, [ length ]) function is used to extract a portion of a string. It returns the substring from the str string, starting from the character number's start, and its length is the number of characters to extract. If the length is not given as an argument to the function, then the remaining string from the starting position to the end of the string is extracted. If the starting position is less than 1, then it is treated as if it were one. If the starting position is greater than the number of characters in the string, it returns the null string. If the length is present but less than or equal to zero, it returns the null string. The first character of the string is character number ...