Awk built-in functions: split, tolower, toupper, sprintf

Today we will share four commonly used awk built-in string functions:

• split(String, A, [Ere])
  Splits the parameter specified by the String parameter into the array elements A[1], A[2], . . ., A[n], and returns the value of the n variable. This separation can be done with the extended regular expression specified by the Ere parameter, or with the current field separator (FS special variable) (if no Ere parameter is given)

• tolower( String )
  Returns the string specified by the String parameter, each uppercase character in the string will be changed to lowercase

• toupper( String )
  Returns the string specified by the String parameter, each lowercase character in the string will be changed to uppercase

• sprintf( Format, Expr, …)
  Formats the expression specified by the Expr parameter according to the printf subroutine format string specified by the Format parameter and returns the resulting string.

Syntax

awk 'pattern {  action }'

Example

awk 'BEGIN { 
    str = "a b c d";
    split(str, arr, " ");
    print arr[3];
}'

In the following example, we use the awk tolower function to convert all strings to lowercase.

awk 'BEGIN { 
    str = "Linux Command Site！";
    newStr = tolower(str);
    print newStr;
}'

In the following example, we use the awk toupper function to convert all strings to uppercase.

awk 'BEGIN { 
    str = "Linux Command Site！";
    newStr = toupper(str);
    print newStr;
}'

In the following example, we use the awk sprintf function to convert the string according to the format.

awk 'BEGIN { 
    str = "%s Command Site！";
    newStr = sprintf(str, "Linux");
    print newStr;
}'