mv: přesouvat soubory

Originální popis anglicky: mv - move files

Návod, kniha: POSIX Programmer's Manual

STRUČNĚ

mv [-fi] source_file target_file mv [-fi] source_file ... target_file

POPIS / INSTRUKCE

In the first synopsis form, the mv utility shall move the file named by the source_file operand to the destination specified by the target_file. This first synopsis form is assumed when the final operand does not name an existing directory and is not a symbolic link referring to an existing directory. In the second synopsis form, mv shall move each file named by a source_file operand to a destination file in the existing directory named by the target_dir operand, or referenced if target_dir is a symbolic link referring to an existing directory. The destination path for each source_file shall be the concatenation of the target directory, a single slash character, and the last pathname component of the source_file. This second form is assumed when the final operand names an existing directory. If any operand specifies an existing file of a type not specified by the System Interfaces volume of IEEE Std 1003.1-2001, the behavior is implementation-defined. For each source_file the following steps shall be taken:

1.

If the destination path exists, the -f option is not specified, and either of the following conditions is true:

the mv utility shall write a prompt to standard error and read a line from standard input. If the response is not affirmative, mv shall do nothing more with the current source_file and go on to any remaining source_files.

2.

The mv utility shall perform actions equivalent to the rename() function defined in the System Interfaces volume of IEEE Std 1003.1-2001, called with the following arguments:

If this succeeds, mv shall do nothing more with the current source_file and go on to any remaining source_files. If this fails for any reasons other than those described for the errno [EXDEV] in the System Interfaces volume of IEEE Std 1003.1-2001, mv shall write a diagnostic message to standard error, do nothing more with the current source_file, and go on to any remaining source_files.

3.

If the destination path exists, and it is a file of type directory and source_file is not a file of type directory, or it is a file not of type directory and source_file is a file of type directory, mv shall write a diagnostic message to standard error, do nothing more with the current source_file, and go on to any remaining source_files.

4.

If the destination path exists, mv shall attempt to remove it. If this fails for any reason, mv shall write a diagnostic message to standard error, do nothing more with the current source_file, and go on to any remaining source_files.

5.

The file hierarchy rooted in source_file shall be duplicated as a file hierarchy rooted in the destination path. If source_file or any of the files below it in the hierarchy are symbolic links, the links themselves shall be duplicated, including their contents, rather than any files to which they refer. The following characteristics of each file in the file hierarchy shall be duplicated:

If the user ID, group ID, or file mode of a regular file cannot be duplicated, the file mode bits S_ISUID and S_ISGID shall not be duplicated. When files are duplicated to another file system, the implementation may require that the process invoking mv has read access to each file being duplicated. If the duplication of the file hierarchy fails for any reason, mv shall write a diagnostic message to standard error, do nothing more with the current source_file, and go on to any remaining source_files. If the duplication of the file characteristics fails for any reason, mv shall write a diagnostic message to standard error, but this failure shall not cause mv to modify its exit status.

6.

The file hierarchy rooted in source_file shall be removed. If this fails for any reason, mv shall write a diagnostic message to the standard error, do nothing more with the current source_file, and go on to any remaining source_files.

OPTIONS

The mv utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines. The following options shall be supported:

-f

Do not prompt for confirmation if the destination path exists. Any previous occurrence of the -i option is ignored.

-i

Prompt for confirmation if the destination path exists. Any previous occurrence of the -f option is ignored.

 

Specifying more than one of the -f or -i options shall not be considered an error. The last option specified shall determine the behavior of mv.

OPERANDS

The following operands shall be supported:

source_file

A pathname of a file or directory to be moved.

target_file

A new pathname for the file or directory being moved.

target_dir

A pathname of an existing directory into which to move the input files.

 

STDIN

The standard input shall be used to read an input line in response to each prompt specified in the STDERR section. Otherwise, the standard input shall not be used.

INPUT FILES

The input files specified by each source_file operand can be of any file type.

ENVIRONMENT VARIABLES

The following environment variables shall affect the execution of mv:

LANG

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.)

LC_ALL

If set to a non-empty string value, override the values of all the other internationalization variables.

LC_COLLATE

 

Determine the locale for the behavior of ranges, equivalence classes, and multi-character collating elements used in the extended regular expression defined for the yesexpr locale keyword in the LC_MESSAGES category.

LC_CTYPE

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 and input files), the behavior of character classes used in the extended regular expression defined for the yesexpr locale keyword in the LC_MESSAGES category.

LC_MESSAGES

Determine the locale for the processing of affirmative responses that should be used to affect the format and contents of diagnostic messages written to standard error.

NLSPATH

Determine the location of message catalogs for the processing of LC_MESSAGES .

 

ASYNCHRONOUS EVENTS

Default.

STDOUT

Not used.

STDERR

Prompts shall be written to the standard error under the conditions specified in the DESCRIPTION section. The prompts shall contain the destination pathname, but their format is otherwise unspecified. Otherwise, the standard error shall be used only for diagnostic messages.

OUTPUT FILES

The output files may be of any file type.

EXTENDED DESCRIPTION

None.

EXIT STATUS

The following exit values shall be returned:

 0

All input files were moved successfully.

>0

An error occurred.

 

CONSEQUENCES OF ERRORS

If the copying or removal of source_file is prematurely terminated by a signal or error, mv may leave a partial copy of source_file at the source or destination. The mv utility shall not modify both source_file and the destination path simultaneously; termination at any point shall leave either source_file or the destination path complete. The following sections are informative.

APPLICATION USAGE

Some implementations mark for update the st_ctime field of renamed files and some do not. Applications which make use of the st_ctime field may behave differently with respect to renamed files unless they are designed to allow for either behavior.

PŘÍKLADY POUŽITÍ

If the current directory contains only files a (of any type defined by the System Interfaces volume of IEEE Std 1003.1-2001), b (also of any type), and a directory c: results with the original files a and b residing in the directory d in the current directory.

RATIONALE

Early proposals diverged from the SVID and BSD historical practice in that they required that when the destination path exists, the -f option is not specified, and input is not a terminal, mv fails. This was done for compatibility with cp. The current text returns to historical practice. It should be noted that this is consistent with the rename() function defined in the System Interfaces volume of IEEE Std 1003.1-2001, which does not require write permission on the target. For absolute clarity, paragraph (1), describing the behavior of mv when prompting for confirmation, should be interpreted in the following manner: The -i option exists on BSD systems, giving applications and users a way to avoid accidentally unlinking files when moving others. When the standard input is not a terminal, the 4.3 BSD mv deletes all existing destination paths without prompting, even when -i is specified; this is inconsistent with the behavior of the 4.3 BSD cp utility, which always generates an error when the file is unwritable and the standard input is not a terminal. The standard developers decided that use of -i is a request for interaction, so when the destination path exists, the utility takes instructions from whatever responds to standard input. The rename() function is able to move directories within the same file system. Some historical versions of mv have been able to move directories, but not to a different file system. The standard developers considered that this was an annoying inconsistency, so this volume of IEEE Std 1003.1-2001 requires directories to be able to be moved even across file systems. There is no -R option to confirm that moving a directory is actually intended, since such an option was not required for moving directories in historical practice. Requiring the application to specify it sometimes, depending on the destination, seemed just as inconsistent. The semantics of the rename() function were preserved as much as possible. For example, mv is not permitted to "rename" files to or from directories, even though they might be empty and removable. Historic implementations of mv did not exit with a non-zero exit status if they were unable to duplicate any file characteristics when moving a file across file systems, nor did they write a diagnostic message for the user. The former behavior has been preserved to prevent scripts from breaking; a diagnostic message is now required, however, so that users are alerted that the file characteristics have changed. The exact format of the interactive prompts is unspecified. Only the general nature of the contents of prompts are specified because implementations may desire more descriptive prompts than those used on historical implementations. Therefore, an application not using the -f option or using the -i option relies on the system to provide the most suitable dialog directly with the user, based on the behavior specified. When mv is dealing with a single file system and source_file is a symbolic link, the link itself is moved as a consequence of the dependence on the rename() functionality, per the DESCRIPTION. Across file systems, this has to be made explicit.

FUTURE DIRECTIONS

None.

SOUVISEJÍCÍ

cp , ln , the System Interfaces volume of IEEE Std 1003.1-2001, rename()

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 .