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.
dot — execute commands in the current environment
The shell shall execute commands from the file in the current environment.
If file does not contain a <slash>, the shell shall use the search path specified by PATH to find the directory containing file. Unlike normal command search, however, the file searched for by the dot utility need not be executable. If no readable file is found, a non-interactive shell shall abort; an interactive shell shall write a diagnostic message to standard error, but this condition shall not be considered a syntax error.
The standard error shall be used only for diagnostic messages.
If no readable file was found or if the commands in the file could not be parsed, and the shell is interactive (and therefore does not abort; see Section 2.8.1, Consequences of Shell Errors), the exit status shall be non-zero. Otherwise, return the value of the last command executed, or a zero exit status if no command is executed.
The following sections are informative.
echo $foo $bar
Some older implementations searched the current directory for the file, even if the value of PATH disallowed it. This behavior was omitted from this volume of POSIX.1‐2008 due to concerns about introducing the susceptibility to trojan horses that the user might be trying to avoid by leaving dot out of PATH.
The KornShell version of dot takes optional arguments that are set to the positional parameters. This is a valid extension that allows a dot script to behave identically to a function.
Section 2.14, Special Built-In Utilities, return
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 http://www.unix.org/online.html .
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