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diff --git a/man-pages-posix-2003/man1p/unset.1p b/man-pages-posix-2003/man1p/unset.1p new file mode 100644 index 0000000..3cbd6b4 --- /dev/null +++ b/man-pages-posix-2003/man1p/unset.1p @@ -0,0 +1,147 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "UNSET" 1P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" unset +.SH PROLOG +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. +.SH NAME +unset \- unset values and attributes of variables and functions +.SH SYNOPSIS +.LP +\fBunset\fP \fB[\fP\fB-fv\fP\fB]\fP \fIname\fP \fB...\fP +.SH DESCRIPTION +.LP +Each variable or function specified by \fIname\fP shall be unset. +.LP +If \fB-v\fP is specified, \fIname\fP refers to a variable name and +the shell shall unset it and remove it from the +environment. Read-only variables cannot be unset. +.LP +If \fB-f\fP is specified, \fIname\fP refers to a function and the +shell shall unset the function definition. +.LP +If neither \fB-f\fP nor \fB-v\fP is specified, \fIname\fP refers to +a variable; if a variable by that name does not exist, it +is unspecified whether a function by that name, if any, shall be unset. +.LP +Unsetting a variable or function that was not previously set shall +not be considered an error and does not cause the shell to +abort. +.LP +The \fIunset\fP special built-in shall support the Base Definitions +volume of IEEE\ Std\ 1003.1-2001, Section 12.2, Utility Syntax Guidelines. +.LP +Note that: +.sp +.RS +.nf + +\fBVARIABLE= +\fP +.fi +.RE +.LP +is not equivalent to an \fIunset\fP of \fBVARIABLE\fP; in the example, +\fBVARIABLE\fP is set to \fB""\fP . Also, the +variables that can be \fIunset\fP should not be misinterpreted to +include the special parameters (see \fISpecial Parameters\fP ). +.SH OPTIONS +.LP +See the DESCRIPTION. +.SH OPERANDS +.LP +See the DESCRIPTION. +.SH STDIN +.LP +Not used. +.SH INPUT FILES +.LP +None. +.SH ENVIRONMENT VARIABLES +.LP +None. +.SH ASYNCHRONOUS EVENTS +.LP +Default. +.SH STDOUT +.LP +Not used. +.SH STDERR +.LP +The standard error shall be used only for diagnostic messages. +.SH OUTPUT FILES +.LP +None. +.SH EXTENDED DESCRIPTION +.LP +None. +.SH EXIT STATUS +.TP 7 +\ 0 +All \fIname\fP operands were successfully unset. +.TP 7 +>0 +At least one \fIname\fP could not be unset. +.sp +.SH CONSEQUENCES OF ERRORS +.LP +Default. +.LP +\fIThe following sections are informative.\fP +.SH APPLICATION USAGE +.LP +None. +.SH EXAMPLES +.LP +Unset \fIVISUAL\fP variable: +.sp +.RS +.nf + +\fBunset -v VISUAL +\fP +.fi +.RE +.LP +Unset the functions \fBfoo\fP and \fBbar\fP: +.sp +.RS +.nf + +\fBunset -f foo bar +\fP +.fi +.RE +.SH RATIONALE +.LP +Consideration was given to omitting the \fB-f\fP option in favor of +an +\fIunfunction\fP utility, but the standard developers decided to retain +historical +practice. +.LP +The \fB-v\fP option was introduced because System V historically used +one name space for both variables and functions. When +\fIunset\fP is used without options, System V historically unset either +a function or a variable, and there was no confusion about +which one was intended. A portable POSIX application can use \fIunset\fP +without an option to unset a variable, but not a +function; the \fB-f\fP option must be used. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fISpecial Built-In Utilities\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 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 . |