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
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.1‐2017 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 1003.1-2017, 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 .
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