Printf bash builtin

Revision as of 13:44, 9 February 2014 by Admin (Talk | contribs)

The printf command is one of a set of Bash Builtin Commands. It provides a method to print pre-formatted text, expanding shells script standard output over the echo command. See format and example below:

printf <FORMAT> <ARGUMENTS...>
printf "Last name: %s\nName: %s\n" "$SURNAME" "$LASTNAME"

printf does not automatically line feed unlike the echo command. LF is not implied, it must be stated. See two equivalents below:

echo "Hello World"
printf "Hello World\n"
printf "%s\n" "Hello World" 

Use of %s formatting argument will also allow it to be applied to multiple lines. The following example will output a linefeed for each of the lines in the printf statement.

printf "%s\n" "I have eaten" "the plums" "that were in" "the icebox"

The format is a character string which contains three types of objects: plain characters, which are simply copied to standard output, character escape sequences, which are converted and copied to the standard output, and format specifications, each of which causes printing of the next successive argument. In addition to the standard printf, `%b' causes printf to expand backslash escape sequences in the corresponding argument, and `%q' causes printf to output the corresponding argument in a format that can be reused as shell input. To print a literal % (percent-sign), use %% in the format string. Every format specifier expects an associated argument. If the format requires more arguments than are supplied, the extra format specifications behave as if a zero value or null string.

Last modified on 9 February 2014, at 13:44