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Manual page for echo(1)

echo - echo arguments

SYNOPSIS

/usr/bin/echo [string...]

AVAILABILITY

SUNWcsu

DESCRIPTION

The echo utility writes its arguments, separated by BLANKs and terminated by a NEWLINE, to the standard output. If there are no arguments, only the NEWLINE character will be written.

echo is useful for producing diagnostics in command files, for sending known data into a pipe, and for displaying the contents of environment variables.

The C shell, the Korn shell, and the Bourne shell each have an echo built-in command, which, by default, will have precedence, and will be invoked if the user calls echo without a full pathname. See shell_builtins.1 sh's echo, ksh's echo, and /usr/bin/echo understand the black-slashed escape characters, except that sh's echo does not understand \a as the alert character; however, these commands do not have a -n option. csh's echo and /usr/ucb/echo, on the other hand, have a -n option, but do not understand the back-slashed escape characters.

OPERANDS

The following operands are supported:

string: A string to be written to standard output. If any operand is ``-n'', it will be treated as a string, not an option. The following character sequences will be recognized within any of the arguments:

\a: alert character
\b: backspace
\c: print line without new-line
\f: form-feed
\n: new-line
\r: carriage return
\t: tab
\v: vertical tab
\\: backslash
\0n: where n is the 8-bit character whose ASCII code is the 1-, 2- or 3-digit octal number representing that character.

USAGE

Portable applications should not use -n (as the first argument) or escape sequences.

The printf.1 utility can be used portably to emulate any of the traditional behaviours of the echo utility as follows:

The Solaris 2.x /usr/bin/echo is equivalent to:

: printf "%b\n" "$*"

The /usr/ucb/echo is equivalent to:

if [ "X$1" = "X-n" ]
then
        shift
        printf "%s" "$*"
else
        printf "%s\n" "$*"
fi

New applications are encouraged to use printf instead of echo.

EXAMPLES

You can use echo to determine how many subdirectories below the root directory (/) is your current directory, as follows:

echo your current-working-directory's full pathname
pipe the output through tr to translate the path's embedded slash-characters into space-characters
pipe that output through wc -w for a count of the names in your path.

: example% /usr/bin/echo $PWD | tr '/' ' ' | wc -w

: See tr.1 and wc.1 for their functionality.

Below are the different flavors for echoing a string without a NEWLINE:

/usr/bin/echo

: % /usr/bin/echo "$USER's current directory is $PWD\c"

sh/ksh shells

: $ echo "$USER's current directory is $PWD\c"

csh shell

: % echo -n "$USER's current directory is $PWD"

/usr/ucb/echo

: % /usr/ucb/echo -n "$USER's current directory is $PWD"

ENVIRONMENT

See environ.5 for descriptions of the following environment variables that affect the execution of echo: LC_CTYPE, LC_MESSAGES, and NLSPATH.

EXIT STATUS

The following error values are returned:

0: Successful completion.
>0: An error occurred.

NOTES

When representing an 8-bit character by using the escape convention \0n, the n must always be preceded by the digit zero (0).

For example, typing: echo 'WARNING:\07' will print the phrase WARNING: and sound the ``bell'' on your terminal. The use of single (or double) quotes (or two backslashes) is required to protect the ``\'' that precedes the ``07''.

Following the \0, up to three digits are used in constructing the octal output character. If, following the \0n, you want to echo additional digits that are not part of the octal representation, you must use the full 3-digit n. For example, if you want to echo ``ESC 7'' you must use the three digits ``033'' rather than just the two digits ``33'' after the \0.

2 digits Incorrect: echo "\0337" | od -xc produces: df0a (hex) 337 (ascii)

3 digits Correct: echo "\00337" | od -xc produces: lb37 0a00 (hex) 033 7 (ascii)

For the octal equivalents of each character, see ascii.5

Last modified 21/April/97