exec(1) 							   User Commands							   exec(1)

NAME

       exec, eval, source - shell built-in functions to execute other commands

SYNOPSIS

   sh
       exec [argument...]

       eval [argument...]

   csh
       exec command

       eval argument...

       source [-h] name

   ksh
       *exec [arg...]

       *eval [arg...]

DESCRIPTION

   sh
       The  exec  command specified by the arguments is executed in place of this shell without creating a new process. Input/output arguments may
       appear and, if no other arguments are given, cause the shell input/output to be modified.

       The arguments to the eval built-in are read as input to the shell and the resulting command(s) executed.

   csh
       exec executes command in place of the current shell, which terminates.

       eval reads its arguments as input to the shell and executes the resulting command(s). This is usually used to execute commands generated as
       the result of command or variable substitution.

       source  reads  commands	from name. source commands may be nested, but if they are nested too deeply the shell may run out of file descrip-
       tors. An error in a sourced file at any level terminates all nested source commands.

       -h	Place commands from the file name on the history list without executing them.

   ksh
       With the exec built-in, if arg is given, the command specified by the arguments is executed in place of this shell without creating  a  new
       process.  Input/output arguments may appear and affect the current process. If no arguments are given the effect of this command is to mod-
       ify file descriptors as prescribed by the input/output redirection list.  In this case, any file descriptor numbers greater than 2 that are
       opened with this mechanism are closed when invoking another program.

       The arguments to eval are read as input to the shell and the resulting command(s) executed.

       On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:

       1.  Variable assignment lists preceding the command remain in effect when the command completes.

       2.  I/O redirections are processed after variable assignments.

       3.  Errors cause a script that contains them to abort.

       4.  Words,  following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
	   able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation  are  not
	   performed.

EXIT STATUS

       For ksh:

       If  command is not found, the exit status is 127. If command is found, but is not an executable utility, the exit status is 126. If a redi-
       rection error occurs, the shell exits with a value in the range 1-125. Otherwise, exec returns a zero exit status.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       csh(1), ksh(1), sh(1), attributes(5)

SunOS 5.10							    17 Jul 2002 							   exec(1)