вернуть директорию часть пути (return the directory portion of a pathname)
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)
dirname — return the directory portion of a pathname
Синопсис (Synopsis)
dirname string
Описание (Description)
The string operand shall be treated as a pathname, as defined in
the Base Definitions volume of POSIX.1‐2017, Section 3.271,
Pathname. The string string shall be converted to the name of
the directory containing the filename corresponding to the last
pathname component in string, performing actions equivalent to
the following steps in order:
1. If string is //, skip steps 2 to 5.
2. If string consists entirely of <slash> characters, string
shall be set to a single <slash> character. In this case,
skip steps 3 to 8.
3. If there are any trailing <slash> characters in string, they
shall be removed.
4. If there are no <slash> characters remaining in string,
string shall be set to a single <period> character. In this
case, skip steps 5 to 8.
5. If there are any trailing non-<slash> characters in string,
they shall be removed.
6. If the remaining string is //, it is implementation-defined
whether steps 7 and 8 are skipped or processed.
7. If there are any trailing <slash> characters in string, they
shall be removed.
8. If the remaining string is empty, string shall be set to a
single <slash> character.
The resulting string shall be written to standard output.
Параметры (Options)
None.
Операнды (Operands)
The following operand shall be supported:
string A string.
Стандартный ввод (Stdin)
Not used.
Входные файлы (Input files)
None.
Переменные окружения (Environment variables)
The following environment variables shall affect the execution of
dirname:
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_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).
LC_MESSAGES
Determine the locale 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.
Асинхронные события (Asynchronous events)
Default.
Стандартный вывод (Stdout)
The dirname utility shall write a line to the standard output in
the following format:
"%s\n", <resulting string>
Стандартный вывод сообщений (Stderr)
The standard error shall be used only for diagnostic messages.
Выходные файлы (Output files)
None.
Расширенное описание (Extended description)
None.
Статус выхода (Exit)
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
Последствия ошибок (Consequences of errors)
Default.
The following sections are informative.
Использование в приложениях (Application usage)
The definition of pathname specifies implementation-defined
behavior for pathnames starting with two <slash> characters.
Therefore, applications shall not arbitrarily add <slash>
characters to the beginning of a pathname unless they can ensure
that there are more or less than two or are prepared to deal with
the implementation-defined consequences.
Примеры (Examples)
The EXAMPLES section of the basename() function (see the System
Interfaces volume of POSIX.1‐2017, basename(3p)) includes a table
showing examples of the results of processing several sample
pathnames by the basename() and dirname() functions and by the
basename and dirname utilities.
See also the examples for the basename utility.
Обоснование (Rationale)
The behaviors of basename and dirname in this volume of
POSIX.1‐2017 have been coordinated so that when string is a valid
pathname:
$(basename -- "string")
would be a valid filename for the file in the directory:
$(dirname -- "string")
This would not work for the versions of these utilities in early
proposals due to the way processing of trailing <slash>
characters was specified. Consideration was given to leaving
processing unspecified if there were trailing <slash> characters,
but this cannot be done; the Base Definitions volume of
POSIX.1‐2017, Section 3.271, Pathname allows trailing <slash>
characters. The basename and dirname utilities have to specify
consistent handling for all valid pathnames.
Будущие направления (Future directions)
None.
Смотри также (See also)
Section 2.5, Parameters and Variables, basename(1p)
The Base Definitions volume of POSIX.1‐2017, Section 3.271,
Pathname, Chapter 8, Environment Variables
The System Interfaces volume of POSIX.1‐2017, basename(3p),
dirname(3p)
