What is "printf"

printf ("print formatted") is a shell builtin (and utility program) that formats and prints data. It accepts a format string, which specifies methods for formatting items, and a list of items to be formatted. Named for the intention of printing to a printer, it 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.

See printf function for more details.