linux man page for eval

EVAL(P) 						     POSIX Programmer's Manual							   EVAL(P)

NAME
       eval - construct command by concatenating arguments

SYNOPSIS
       eval [argument ...]

DESCRIPTION
       The  eval  utility  shall  construct a command by concatenating arguments together, separating each with a <space>. The constructed command
       shall be read and executed by the shell.

OPTIONS
       None.

OPERANDS
       See the DESCRIPTION.

STDIN
       Not used.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       None.

ASYNCHRONOUS EVENTS
       Default.

STDOUT
       Not used.

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       None.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       If there are no arguments, or only null arguments, eval shall return a zero exit status; otherwise, it shall return the exit status of  the
       command defined by the string of concatenated arguments separated by <space>s.

CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       None.

EXAMPLES
	      foo=10 x=foo
	      y='$'$x
	      echo $y
	      $fooeval y='$'$x
	      echo $y
	      10

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Special Built-In Utilities

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical  and	Electronics  Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
       and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can  be  obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								   EVAL(P)