Classic Shell Scripting

The Full Story on printf

We introduced the printf command in Section 2.5.4. This section completes the description of that command.

printf

Usage

printf format [ string ... ]

Purpose

To produce output from shell scripts. Since printf's behavior is defined by the POSIX standard, scripts that use it can be more portable than those that use echo.

Major options

None.

Behavior

printf uses the format string to control the output. Plain characters in the string are printed. Escape sequences as described for echo are interpreted. Format specifiers consisting of % and a letter direct formatting of corresponding argument strings. See text for details.

As we saw earlier, the full syntax of the printf command has two parts:

printf format-string [arguments ...]

The first part is a string that describes the format specifications; this is best supplied as a string constant in quotes. The second part is an argument list, such as a list of strings or variable values, that correspond to the format specifications. The format string combines text to be output literally with specifications describing how to format subsequent arguments on the printf command line. Regular characters are printed verbatim. Escape sequences, similar to those of echo, are interpreted and then output as the corresponding character. Format specifiers, which begin with the character % and end with one of a defined set of letters, control the output of the following corresponding arguments. printf's escape sequences are described in ...