diff options
Diffstat (limited to 'man-pages-posix-2003/man1p/cd.1p')
| -rw-r--r-- | man-pages-posix-2003/man1p/cd.1p | 355 |
1 files changed, 355 insertions, 0 deletions
diff --git a/man-pages-posix-2003/man1p/cd.1p b/man-pages-posix-2003/man1p/cd.1p new file mode 100644 index 0000000..36322c1 --- /dev/null +++ b/man-pages-posix-2003/man1p/cd.1p @@ -0,0 +1,355 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "CD" 1P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" cd +.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 +cd \- change the working directory +.SH SYNOPSIS +.LP +\fBcd\fP \fB[\fP\fB-L | -P\fP\fB] [\fP\fIdirectory\fP\fB]\fP\fB +.br +.sp +cd - +.br +\fP +.SH DESCRIPTION +.LP +The \fIcd\fP utility shall change the working directory of the current +shell execution environment (see \fIShell Execution Environment\fP +) by executing the following steps in sequence. (In the +following steps, the symbol \fBcurpath\fP represents an intermediate +value used to simplify the description of the algorithm used +by \fIcd\fP. There is no requirement that \fBcurpath\fP be made visible +to the application.) +.IP " 1." 4 +If no \fIdirectory\fP operand is given and the \fIHOME\fP environment +variable is empty or undefined, the default behavior is +implementation-defined and no further steps shall be taken. +.LP +.IP " 2." 4 +If no \fIdirectory\fP operand is given and the \fIHOME\fP environment +variable is set to a non-empty value, the \fIcd\fP +utility shall behave as if the directory named in the \fIHOME\fP environment +variable was specified as the \fIdirectory\fP +operand. +.LP +.IP " 3." 4 +If the \fIdirectory\fP operand begins with a slash character, set +\fBcurpath\fP to the operand and proceed to step 7. +.LP +.IP " 4." 4 +If the first component of the \fIdirectory\fP operand is dot or dot-dot, +proceed to step 6. +.LP +.IP " 5." 4 +Starting with the first pathname in the colon-separated pathnames +of \fICDPATH\fP (see the ENVIRONMENT VARIABLES section) if +the pathname is non-null, test if the concatenation of that pathname, +a slash character, and the \fIdirectory\fP operand names a +directory. If the pathname is null, test if the concatenation of dot, +a slash character, and the operand names a directory. In +either case, if the resulting string names an existing directory, +set \fBcurpath\fP to that string and proceed to step 7. +Otherwise, repeat this step with the next pathname in \fICDPATH\fP +until all pathnames have been tested. +.LP +.IP " 6." 4 +Set \fBcurpath\fP to the string formed by the concatenation of the +value of \fIPWD\fP, a slash character, and the +operand. +.LP +.IP " 7." 4 +If the \fB-P\fP option is in effect, the \fIcd\fP utility shall perform +actions equivalent to the \fIchdir\fP() function, called with \fBcurpath\fP +as the \fIpath\fP argument. If these actions +succeed, the \fIPWD\fP environment variable shall be set to an absolute +pathname for the current working directory and shall not +contain filename components that, in the context of pathname resolution, +refer to a file of type symbolic link. If there is +insufficient permission on the new directory, or on any parent of +that directory, to determine the current working directory, the +value of the \fIPWD\fP environment variable is unspecified. If the +actions equivalent to \fIchdir\fP() fail for any reason, the \fIcd\fP +utility shall display an appropriate error message +and not alter the \fIPWD\fP environment variable. Whether the actions +equivalent to \fIchdir\fP() succeed or fail, no further steps shall +be taken. +.LP +.IP " 8." 4 +The \fBcurpath\fP value shall then be converted to canonical form +as follows, considering each component from beginning to end, +in sequence: +.RS +.IP " a." 4 +Dot components and any slashes that separate them from the next component +shall be deleted. +.LP +.IP " b." 4 +For each dot-dot component, if there is a preceding component and +it is neither root nor dot-dot, the preceding component, all +slashes separating the preceding component from dot-dot, dot-dot and +all slashes separating dot-dot from the following component +shall be deleted. +.LP +.IP " c." 4 +An implementation may further simplify \fBcurpath\fP by removing any +trailing slash characters that are not also leading +slashes, replacing multiple non-leading consecutive slashes with a +single slash, and replacing three or more leading slashes with a +single slash. If, as a result of this canonicalization, the \fBcurpath\fP +variable is null, no further steps shall be taken. +.LP +.RE +.LP +.IP " 9." 4 +The \fIcd\fP utility shall then perform actions equivalent to the +\fIchdir\fP() function +called with \fBcurpath\fP as the \fIpath\fP argument. If these actions +failed for any reason, the \fIcd\fP utility shall display +an appropriate error message and no further steps shall be taken. +The \fIPWD\fP environment variable shall be set to +\fBcurpath\fP. +.LP +.LP +If, during the execution of the above steps, the \fIPWD\fP environment +variable is changed, the \fIOLDPWD\fP environment +variable shall also be changed to the value of the old working directory +(that is the current working directory immediately prior +to the call to \fIcd\fP). +.SH OPTIONS +.LP +The \fIcd\fP utility shall conform to the Base Definitions volume +of IEEE\ Std\ 1003.1-2001, Section 12.2, Utility Syntax Guidelines. +.LP +The following options shall be supported by the implementation: +.TP 7 +\fB-L\fP +Handle the operand dot-dot logically; symbolic link components shall +not be resolved before dot-dot components are processed +(see steps 8. and 9. in the DESCRIPTION). +.TP 7 +\fB-P\fP +Handle the operand dot-dot physically; symbolic link components shall +be resolved before dot-dot components are processed (see +step 7. in the DESCRIPTION). +.sp +.LP +If both \fB-L\fP and \fB-P\fP options are specified, the last of these +options shall be used and all others ignored. If +neither \fB-L\fP nor \fB-P\fP is specified, the operand shall be handled +dot-dot logically; see the DESCRIPTION. +.SH OPERANDS +.LP +The following operands shall be supported: +.TP 7 +\fIdirectory\fP +An absolute or relative pathname of the directory that shall become +the new working directory. The interpretation of a relative +pathname by \fIcd\fP depends on the \fB-L\fP option and the \fICDPATH\fP +and \fIPWD\fP environment variables. If +\fIdirectory\fP is an empty string, the results are unspecified. +.TP 7 +- +When a hyphen is used as the operand, this shall be equivalent to +the command: +.sp +.RS +.nf + +\fBcd "$OLDPWD" && pwd +\fP +.fi +.RE +.LP +which changes to the previous working directory and then writes its +name. +.sp +.SH STDIN +.LP +Not used. +.SH INPUT FILES +.LP +None. +.SH ENVIRONMENT VARIABLES +.LP +The following environment variables shall affect the execution of +\fIcd\fP: +.TP 7 +\fICDPATH\fP +A colon-separated list of pathnames that refer to directories. The +\fIcd\fP utility shall use this list in its attempt to +change the directory, as described in the DESCRIPTION. An empty string +in place of a directory pathname represents the current +directory. If \fICDPATH\fP is not set, it shall be treated as if it +were an empty string. +.TP 7 +\fIHOME\fP +The name of the directory, used when no \fIdirectory\fP operand is +specified. +.TP 7 +\fILANG\fP +Provide a default value for the internationalization variables that +are unset or null. (See the Base Definitions volume of +IEEE\ Std\ 1003.1-2001, Section 8.2, Internationalization Variables +for +the precedence of internationalization variables used to determine +the values of locale categories.) +.TP 7 +\fILC_ALL\fP +If set to a non-empty string value, override the values of all the +other internationalization variables. +.TP 7 +\fILC_CTYPE\fP +Determine the locale for the interpretation of sequences of bytes +of text data as characters (for example, single-byte as +opposed to multi-byte characters in arguments). +.TP 7 +\fILC_MESSAGES\fP +Determine the locale that should be used to affect the format and +contents of diagnostic messages written to standard +error. +.TP 7 +\fINLSPATH\fP +Determine the location of message catalogs for the processing of \fILC_MESSAGES +\&.\fP +.TP 7 +\fIOLDPWD\fP +A pathname of the previous working directory, used by \fIcd\fP \fB-\fP. +.TP 7 +\fIPWD\fP +This variable shall be set as specified in the DESCRIPTION. If an +application sets or unsets the value of \fIPWD\fP, the +behavior of \fIcd\fP is unspecified. +.sp +.SH ASYNCHRONOUS EVENTS +.LP +Default. +.SH STDOUT +.LP +If a non-empty directory name from \fICDPATH\fP is used, or if \fIcd\fP +\fB-\fP is used, an absolute pathname of the new +working directory shall be written to the standard output as follows: +.sp +.RS +.nf + +\fB"%s\\n", <\fP\fInew directory\fP\fB> +\fP +.fi +.RE +.LP +Otherwise, there shall be no output. +.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 +.LP +The following exit values shall be returned: +.TP 7 +\ 0 +The directory was successfully changed. +.TP 7 +>0 +An error occurred. +.sp +.SH CONSEQUENCES OF ERRORS +.LP +The working directory shall remain unchanged. +.LP +\fIThe following sections are informative.\fP +.SH APPLICATION USAGE +.LP +Since \fIcd\fP affects the current shell execution environment, it +is always provided as a shell regular built-in. If it is +called in a subshell or separate utility execution environment, such +as one of the following: +.sp +.RS +.nf + +\fB(cd /tmp) +nohup cd +find . -exec cd {} \\; +\fP +.fi +.RE +.LP +it does not affect the working directory of the caller's environment. +.LP +The user must have execute (search) permission in \fIdirectory\fP +in order to change to it. +.SH EXAMPLES +.LP +None. +.SH RATIONALE +.LP +The use of the \fICDPATH\fP was introduced in the System V shell. +Its use is analogous to the use of the \fIPATH\fP variable +in the shell. The BSD C shell used a shell parameter \fIcdpath\fP +for this purpose. +.LP +A common extension when \fIHOME\fP is undefined is to get the login +directory from the user database for the invoking user. +This does not occur on System V implementations. +.LP +Some historical shells, such as the KornShell, took special actions +when the directory name contained a dot-dot component, +selecting the logical parent of the directory, rather than the actual +parent directory; that is, it moved up one level toward the +\fB'/'\fP in the pathname, remembering what the user typed, rather +than performing the equivalent of: +.sp +.RS +.nf + +\fBchdir(".."); +\fP +.fi +.RE +.LP +In such a shell, the following commands would not necessarily produce +equivalent output for all directories: +.sp +.RS +.nf + +\fBcd .. && ls ls .. +\fP +.fi +.RE +.LP +This behavior is now the default. It is not consistent with the definition +of dot-dot in most historical practice; that is, +while this behavior has been optionally available in the KornShell, +other shells have historically not supported this +functionality. The logical pathname is stored in the \fIPWD\fP environment +variable when the \fIcd\fP utility completes and this +value is used to construct the next directory name if \fIcd\fP is +invoked with the \fB-L\fP option. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fIShell Execution Environment\fP, \fIpwd\fP, the System +Interfaces volume of IEEE\ Std\ 1003.1-2001, \fIchdir\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 . |