Escapes
-------
The escapes that `-printf' and `-fprintf' recognize are:
`\a'
Alarm bell.
`\b'
Backspace.
`\c'
Stop printing from this format immediately and flush the output.
`\f'
Form feed.
`\n'
Newline.
`\r'
Carriage return.
`\t'
Horizontal tab.
`\v'
Vertical tab.
`\\'
A literal backslash (`\').
A `\' character followed by any other character is treated as an
ordinary character, so they both are printed, and a warning message is
printed to the standard error output (because it was probably a typo).