Section: POSIX Programmer's Manual (1P)
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.
--- construct command by concatenating arguments
utility shall construct a command by concatenating
together, separating each with a
The constructed command shall be read and executed by the shell.
See the DESCRIPTION.
The standard error shall be used only for diagnostic messages.
If there are no
or only null
shall return a zero exit status; otherwise, it shall return the exit
status of the command defined by the string of concatenated
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
CONSEQUENCES OF ERRORS
The following sections are informative.
is not required to recognize the
end of options delimiter, in cases where the argument(s) to
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
eval " $commands"
eval " $(some_command)"
This standard allows, but does not require,
Although this means applications cannot use
to protect against options supported as an extension (or errors reported
for unsupported options), the nature of the
utility is such that other means can be used to provide this protection
(see APPLICATION USAGE above).
, Special Built-In Utilities
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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
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