удалить записи из каталога (remove directory entries)
Пролог (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.
Имя (Name)
rm — remove directory entries
Синопсис (Synopsis)
rm [-iRr] file...
rm -f [-iRr] [file...]
Описание (Description)
The rm utility shall remove the directory entry specified by each
file argument.
If either of the files dot or dot-dot are specified as the
basename portion of an operand (that is, the final pathname
component) or if an operand resolves to the root directory, rm
shall write a diagnostic message to standard error and do nothing
more with such operands.
For each file the following steps shall be taken:
1. If the file does not exist:
a. If the -f option is not specified, rm shall write a
diagnostic message to standard error.
b. Go on to any remaining files.
2. If file is of type directory, the following steps shall be
taken:
a. If neither the -R option nor the -r option is specified,
rm shall write a diagnostic message to standard error, do
nothing more with file, and go on to any remaining files.
b. If file is an empty directory, rm may skip to step 2d.
If the -f option is not specified, and either the
permissions of file do not permit writing and the
standard input is a terminal or the -i option is
specified, rm shall write a prompt to standard error and
read a line from the standard input. If the response is
not affirmative, rm shall do nothing more with the
current file and go on to any remaining files.
c. For each entry contained in file, other than dot or dot-
dot, the four steps listed here (1 to 4) shall be taken
with the entry as if it were a file operand. The rm
utility shall not traverse directories by following
symbolic links into other parts of the hierarchy, but
shall remove the links themselves.
d. If the -i option is specified, rm shall write a prompt to
standard error and read a line from the standard input.
If the response is not affirmative, rm shall do nothing
more with the current file, and go on to any remaining
files.
3. If file is not of type directory, the -f option is not
specified, and either the permissions of file do not permit
writing and the standard input is a terminal or the -i option
is specified, rm shall write a prompt to the standard error
and read a line from the standard input. If the response is
not affirmative, rm shall do nothing more with the current
file and go on to any remaining files.
4. If the current file is a directory, rm shall perform actions
equivalent to the rmdir() function defined in the System
Interfaces volume of POSIX.1‐2017 called with a pathname of
the current file used as the path argument. If the current
file is not a directory, rm shall perform actions equivalent
to the unlink() function defined in the System Interfaces
volume of POSIX.1‐2017 called with a pathname of the current
file used as the path argument.
If this fails for any reason, rm shall write a diagnostic
message to standard error, do nothing more with the current
file, and go on to any remaining files.
The rm utility shall be able to descend to arbitrary depths in a
file hierarchy, and shall not fail due to path length limitations
(unless an operand specified by the user exceeds system
limitations).
Параметры (Options)
The rm utility shall conform to the Base Definitions volume of
POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
-f Do not prompt for confirmation. Do not write diagnostic
messages or modify the exit status in the case of no
file operands, or in the case of operands that do not
exist. Any previous occurrences of the -i option shall
be ignored.
-i Prompt for confirmation as described previously. Any
previous occurrences of the -f option shall be ignored.
-R Remove file hierarchies. See the DESCRIPTION.
-r Equivalent to -R.
Операнды (Operands)
The following operand shall be supported:
file A pathname of a directory entry to be removed.
Стандартный ввод (Stdin)
The standard input shall be used to read an input line in
response to each prompt specified in the STDOUT section.
Otherwise, the standard input shall not be used.
Входные файлы (Input files)
None.
Переменные окружения (Environment variables)
The following environment variables shall affect the execution of
rm:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base
Definitions volume of POSIX.1‐2017, 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 the behavior of character
classes within regular expressions used in the extended
regular expression defined for the yesexpr locale
keyword in the LC_MESSAGES category.
LC_MESSAGES
Determine the locale used to process affirmative
responses, and the locale used to affect the format and
contents of diagnostic messages and prompts written to
standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Асинхронные события (Asynchronous events)
Default.
Стандартный вывод (Stdout)
Not used.
Стандартный вывод сообщений (Stderr)
Prompts shall be written to standard error under the conditions
specified in the DESCRIPTION and OPTIONS sections. The prompts
shall contain the file pathname, but their format is otherwise
unspecified. The standard error also shall be used for diagnostic
messages.
Выходные файлы (Output files)
None.
Расширенное описание (Extended description)
None.
Статус выхода (Exit)
The following exit values shall be returned:
0 Each directory entry was successfully removed, unless its
removal was canceled by a non-affirmative response to a
prompt for confirmation.
>0 An error occurred.
Последствия ошибок (Consequences of errors)
Default.
The following sections are informative.
Использование в приложениях (Application usage)
The rm utility is forbidden to remove the names dot and dot-dot
in order to avoid the consequences of inadvertently doing
something like:
rm -r .*
Some implementations do not permit the removal of the last link
to an executable binary file that is being executed; see the
[EBUSY] error in the unlink() function defined in the System
Interfaces volume of POSIX.1‐2017. Thus, the rm utility can fail
to remove such files.
The -i option causes rm to prompt and read the standard input
even if the standard input is not a terminal, but in the absence
of -i the mode prompting is not done when the standard input is
not a terminal.
Примеры (Examples)
1. The following command:
rm a.out core
removes the directory entries: a.out and core.
2. The following command:
rm -Rf junk
removes the directory junk and all its contents, without
prompting.
Обоснование (Rationale)
For absolute clarity, paragraphs (2b) and (3) in the DESCRIPTION
of rm describing the behavior when prompting for confirmation,
should be interpreted in the following manner:
if ((NOT f_option) AND
((not_writable AND input_is_terminal) OR i_option))
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.
The -r option is historical practice on all known systems. The
synonym -R option is provided for consistency with the other
utilities in this volume of POSIX.1‐2017 that provide options
requesting recursive descent through the file hierarchy.
The behavior of the -f option in historical versions of rm is
inconsistent. In general, along with ``forcing'' the unlink
without prompting for permission, it always causes diagnostic
messages to be suppressed and the exit status to be unmodified
for nonexistent operands and files that cannot be unlinked. In
some versions, however, the -f option suppresses usage messages
and system errors as well. Suppressing such messages is not a
service to either shell scripts or users.
It is less clear that error messages regarding files that cannot
be unlinked (removed) should be suppressed. Although this is
historical practice, this volume of POSIX.1‐2017 does not permit
the -f option to suppress such messages.
When given the -r and -i options, historical versions of rm
prompt the user twice for each directory, once before removing
its contents and once before actually attempting to delete the
directory entry that names it. This allows the user to ``prune''
the file hierarchy walk. Historical versions of rm were
inconsistent in that some did not do the former prompt for
directories named on the command line and others had obscure
prompting behavior when the -i option was specified and the
permissions of the file did not permit writing. The POSIX Shell
and Utilities rm differs little from historic practice, but does
require that prompts be consistent. Historical versions of rm
were also inconsistent in that prompts were done to both standard
output and standard error. This volume of POSIX.1‐2017 requires
that prompts be done to standard error, for consistency with cp
and mv, and to allow historical extensions to rm that provide an
option to list deleted files on standard output.
The rm utility is required to descend to arbitrary depths so that
any file hierarchy may be deleted. This means, for example, that
the rm utility cannot run out of file descriptors during its
descent (that is, if the number of file descriptors is limited,
rm cannot be implemented in the historical fashion where one file
descriptor is used per directory level). Also, rm is not
permitted to fail because of path length restrictions, unless an
operand specified by the user is longer than {PATH_MAX}.
The rm utility removes symbolic links themselves, not the files
they refer to, as a consequence of the dependence on the unlink()
functionality, per the DESCRIPTION. When removing hierarchies
with -r or -R, the prohibition on following symbolic links has to
be made explicit.
Будущие направления (Future directions)
None.
Смотри также (See also)
rmdir(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines
The System Interfaces volume of POSIX.1‐2017, remove(3p),
rmdir(3p), unlink(3p)
