Printing text

This section describes commands that display text strings.

• echo invocation: Print a line of text.
• printf invocation: Format and print data.
• yes invocation: Print a string until interrupted.

echo: Print a line of text

Synopsis:

echo [ option ]... [ string ]...

echo writes each given string to standard output, with a space between each and a newline after the last one.

The program accepts the following options. Also see section Common options.

`-n'

Do not output the trailing newline.

`-e'

Enable interpretation of the following backslash-escaped characters in each string:

`\a'

alert (bell)

`\b'

backspace

`\c'

suppress trailing newline

`\f'

form feed

`\n'

new line

`\r'

carriage return

`\t'

horizontal tab

`\v'

vertical tab

`\\'

backslash

`\nnn'

the character whose ASCII code is nnn (octal); if nnn is not a valid octal number, it is printed literally.

printf: Format and print data

Synopsis:

printf format [ argument ]...

printf prints the format string, interpreting `%' directives and `\' escapes in the same way as the C printf function. The format argument is re-used as necessary to convert all of the given arguments.

printf has one additional directive, `%b', which prints its argument string with `\' escapes interpreted in the same way as in the format string.

printf interprets `\0ooo' in format as an octal number (if ooo is 0 to 3 octal digits) specifying a character to print, and `\xhhh' as a hexadecimal number (if hhh is 1 to 3 hex digits) specifying a character to print.

An additional escape, `\c', causes printf to produce no further output.

The only options are a lone `--help' or `--version'. See section Common options.

yes: Print a string until interrupted

yes prints the command line arguments, separated by spaces and followed by a newline, forever until it is killed. If no arguments are given, it prints `y' followed by a newline forever until killed.

The only options are a lone `--help' or `--version'. See section Common options.