|Developer(s)||Various open-source and commercial developers|
|Operating system||Unix and Unix-like|
In Unix and Unix-like operating systems, printf ("print formatted") is a shell builtin (and utility program) that formats and prints data.
The command accepts a printf format string, which specifies methods for formatting items, and a list of items to be formatted. Named historically after the intention of printing to a printer, it now actually outputs to stdout. Characters in the format string are copied to the output or, if a
% is encountered, are used to format an item. In addition to the standard formats,
%b causes printf to expand backslash escape sequences (for example
\n for newline), and
%q outputs an item that can be used as shell input. The format string is reused if there are more items than format specs. Unused format specs provide a zero value or null string.
printf is part of the X/Open Portability Guide since issue 4 of 1992. It was inherited into the first version of POSIX.1 and the Single Unix Specification. It first appeared in 4.3BSD-Reno.
The version of
printf bundled in GNU coreutils was written by David MacKenzie. It has an extension %q for escaping strings in POSIX-shell format.
$ for NUMBER in 4 6 8 9 10 > do printf " >> %03d %d<< \n" $NUMBER $RANDOM > done >> 004 26305<< >> 006 6687<< >> 008 20170<< >> 009 28322<< >> 010 4400<<
This will print a directory listing, emulating 'ls':
printf "%s\n" *