Effective awk Programming, 3rd Edition

Chapter 4. Printing Output

One of the most common programming actions is to print, or output, some or all of the input. Use the print statement for simple output, and the printf statement for fancier formatting. The print statement is not limited when computing which values to print. However, with two exceptions, you cannot specify how to print them -- how many columns, whether to use exponential notation or not, and so on. (For the exceptions, see Section 4.3 and Section 4.4 later in this chapter.) For printing with specifications, you need the printf statement (see Section 4.5 later in this chapter).

Besides basic and formatted printing, this chapter also covers I/O redirections to files and pipes, introduces the special filenames that gawk processes internally, and discusses the close built-in function.

The print Statement

The print statement is used to produce output with simple, standardized formatting. Specify only the strings or numbers to print, in a list separated by commas. They are output, separated by single spaces, followed by a newline. The statement looks like this:

print item1, item2, ...

The entire list of items may be optionally enclosed in parentheses. The parentheses are necessary if any of the item expressions uses the > relational operator; otherwise, it could be confused with a redirection (see Section 4.6 later in this chapter).

The items to print can be constant strings or numbers, fields of the current record (such as $1), variables, or any awk