realpath(1) [debian man page]

REALPATH(1)							      Debian							       REALPATH(1)

NAME

       realpath - return the canonicalised absolute pathname

SYNOPSIS

       realpath [-s|--strip] [-z|--zero]  filename  ...
       realpath --h|--help
       realpath --v|--version

DESCRIPTION

       realpath  converts  each filename argument to an absolute pathname, which has no components that are symbolic links or the special .  or ..
       directory entries.  (See realpath(3) for more information.)
       Each path component in the filename must exist, otherwise realpath will fail and non-zero exit status will be returned.
       Please note that mostly the same functionality is provided by the `-e'  option of the readlink(1) command.

       When the -s option is used realpath only removes the .  and ..  directories, but not symbolic links from filename.  If the  given  filename
       argument  is relative (i.e.  does not start with `/'), realpath -s prepends to it the current directory name as obtained from the getcwd(2)
       system call before further processing.

       Each converted pathname is output to the standard output, on its own line.

OPTIONS

       -s, --strip
	    Only strip .  and .., components, but do not resolve symbolic links.

       -z, --zero
	    Separate output filenames with the null character instead of newline, so it can be used with the `-0' option of xargs(1).

       -h, --help
	    Print short usage information.

       -v, --version
	    Show realpath's version number.

EXAMPLES

       For the examples below let's suppose that /usr/bin/X11 is a symbolic link, pointing to directory /usr/bin.

   Example 1
       Regardless of what the current directory is
	   realpath /../usr/bin/X11/./xterm
       prints
	   /usr/bin/xterm
       but
	   realpath -s /../usr/bin/X11/./xterm
       outputs
	   /usr/bin/X11/xterm

   Example 2
       When the current directory is /usr/bin/X11 (which is still a symbolic link to /usr/bin), the output of both
	   realpath ./xterm
       and
	   realpath  -s ./xterm
       will be
	   /usr/bin/xterm

   Example 3
       Providing that the current directory is /home/user (and the directory exists before and during the realpath run), the  command
	   realpath ../path/to/some/./non-existent/./directory/../or/../file
       will fail with the following error
	   ../path/to/some/./non-existent/./directory/../or/../file: No such file or directory
       but
	   realpath -s ../path/to/some/./non-existent/./directory/../or/../file
       will return
	   /home/path/to/some/non-existent/file

EXIT STATUS

       realpath returns a zero exit code when all pathnames were successfully converted.
       In case of any errors (e.g. missing or unavailable directories in the path), realpath prints error message to stderr and returns a non-zero
       exit code.

SEE ALSO

       basename(1), dirname(1), readlink(1), chase(1), realpath(3)

BUGS

       Hopefully none :)
       If  you	find  some, please report them via the normal Debian bug reporting system, see the file /usr/share/doc/debian/bug-reporting.txt in
       the package doc-debian or the reportbug(1) man page.

AUTHOR

       Originally written by Lars Wirzenius <liw@iki.fi>, as a part of the dwww package.  Robert Luberda <robert@debian.org>  currently  maintains
       and extends it.

       realpath  is  licensed  via  the GNU General Public License.  While it has been written for Debian, porting it to other systems is strongly
       encouraged.

Debian								October 16th, 2011						       REALPATH(1)

REALPATH(3P)						     POSIX Programmer's Manual						      REALPATH(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       realpath - resolve a pathname

SYNOPSIS

       #include <stdlib.h>

       char *realpath(const char *restrict file_name,
	      char *restrict resolved_name);

DESCRIPTION

       The realpath() function shall derive, from the pathname pointed to by file_name, an absolute pathname that names the same file, whose reso-
       lution  does  not involve '.', '..', or symbolic links. The generated pathname shall be stored as a null-terminated string, up to a maximum
       of {PATH_MAX} bytes, in the buffer pointed to by resolved_name.

       If resolved_name is a null pointer, the behavior of realpath() is implementation-defined.

RETURN VALUE

       Upon successful completion, realpath() shall return a pointer to the resolved name. Otherwise, realpath() shall return a null  pointer  and
       set errno to indicate the error, and the contents of the buffer pointed to by resolved_name are undefined.

ERRORS

       The realpath() function shall fail if:

       EACCES Read or search permission was denied for a component of file_name.

       EINVAL The file_name argument is a null pointer.

       EIO    An error occurred while reading from the file system.

       ELOOP  A loop exists in symbolic links encountered during resolution of the path argument.

       ENAMETOOLONG
	      The length of the file_name argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.

       ENOENT A component of file_name does not name an existing file or file_name points to an empty string.

       ENOTDIR
	      A component of the path prefix is not a directory.

       The realpath() function may fail if:

       ELOOP  More than {SYMLOOP_MAX} symbolic links were encountered during resolution of the path argument.

       ENAMETOOLONG
	      Pathname resolution of a symbolic link produced an intermediate result whose length exceeds {PATH_MAX}.

       ENOMEM Insufficient storage space is available.

       The following sections are informative.

EXAMPLES

   Generating an Absolute Pathname
       The  following example generates an absolute pathname for the file identified by the symlinkpath argument. The generated pathname is stored
       in the actualpath array.

	      #include <stdlib.h>
	      ...
	      char *symlinkpath = "/tmp/symlink/file";
	      char actualpath [PATH_MAX+1];
	      char *ptr;

	      ptr = realpath(symlinkpath, actualpath);

APPLICATION USAGE

       None.

RATIONALE

       Since the maximum pathname length is arbitrary unless {PATH_MAX} is defined, an application generally cannot supply a resolved_name  buffer
       with size {{PATH_MAX}+1}.

FUTURE DIRECTIONS

       In the future, passing a null pointer to realpath() for the resolved_name argument may be defined to have realpath() allocate space for the
       generated pathname.

SEE ALSO

       getcwd(), sysconf(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- 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 .

IEEE
/The Open Group						       2003							      REALPATH(3P)