This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       Since eval is not required to recognize the "--" end of options delimiter, in cases where the argument(s)
       to  eval might begin with '-' it is recommended that the first argument is prefixed by a string that will
       not alter the commands to be executed, such as a <space> character:

           eval " $commands"

       or:

           eval " $(some_command)"

       Default.

       Default.

       Thefollowingsectionsareinformative.

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for  Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are most likely to have  been  introduced
       during   the   conversion  of  the  source  files  to  man  page  format.  To  report  such  errors,  see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                          EVAL(1POSIX)

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

       None.

       foo=10 x=foo
       y='$'$x
       echo $y
       $foo
       eval y='$'$x
       echo $y
       10

       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> characters, or a non-zero exit status if the concatenation could not be parsed as a  command  and
       the shell is interactive (and therefore did not abort).

       None.

       None.

       None.

       eval — construct command by concatenating arguments

       See the DESCRIPTION.

       None.

       None.

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

       This standard allows, but does not require, eval to recognize "--".   Although  this  means  applications
       cannot  use "--" to protect against options supported as an extension (or errors reported for unsupported
       options), the nature of the eval utility is such that other means can be used to provide this  protection
       (see APPLICATION USAGE above).

Section2.14, SpecialBuilt-InUtilities

       The standard error shall be used only for diagnostic messages.

       Not used.

       Not used.

       eval [argument...]