NAME

echo - write arguments to standard output

 SYNOPSIS

echo [string ...]

 DESCRIPTION

The echo utility will write its arguments to standard output, followed by a newline character. If there are no arguments, only the newline character will be written.

 OPTIONS

The echo utility will not recognise the -- argument in the manner specified by Guideline 10 of the XBD specification, Utility Syntax Guidelines  ; -- will be recognised as a string operand.

Implementations will not support any options.

 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 recognised within any of the arguments:

\a

Write an alert character.

\b

Write a backspace character.

\c

Suppress the newline character that otherwise follows the final argument in the output. All characters following the \c in the arguments will be ignored.

\f

Write a form-feed character.

\n

Write a newline character.

\r

Write a carriage-return character.

\t

Write a tab character.

\v

Write a vertical-tab character.

\\

Write a backslash character.

\0num

Write an 8-bit value that is the zero-, one-, two- or three-digit octal number num .

 STDIN

Not used.

 INPUT FILES

None.

 ENVIRONMENT VARIABLES

The following environment variables affect the execution of echo:

LANG

Provide a default value for the internationalisation variables that are unset or null. If LANG is unset or null, the corresponding value from the implementation-dependent default locale will be used. If any of the internationalisation variables contains an invalid setting, the utility will behave as if none of the variables had been defined.

LC_ALL

If set to a non-empty string value, override the values of all the other internationalisation variables.

LC_CTYPE

Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single- as opposed to multi-byte characters in arguments).

LC_MESSAGES

Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.

NLSPATH

Determine the location of message catalogues for the processing of LC_MESSAGES .

 ASYNCHRONOUS EVENTS

Default.

 STDOUT

The echo utility arguments will be separated by single space characters and a newline character will follow the last argument. Output transformations will occur based on the escape sequences in the input; see the OPERANDS section.

 STDERR

Used only for diagnostic messages.

 OUTPUT FILES

None.

 EXTENDED DESCRIPTION

None.

 EXIT STATUS

The following exit values are returned:

0

Successful completion.

>0

An error occurred.

 CONSEQUENCES OF ERRORS

Default.

 APPLICATION USAGE

It is not possible to use echo portably across all systems that are not XSI-conformant unless both -n (as the first argument) and escape sequences are omitted.

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

• The XSI echo is equivalent to:

  
  printf "%b\n" "$*"
  
  

• The BSD 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

None.

 FUTURE DIRECTIONS

None.

 SEE ALSO

printf.