часть каталога в имени пути (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)
basename — return non-directory portion of a pathname
Синопсис (Synopsis)
basename string [suffix]
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 filename
corresponding to the last pathname component in string and then
the suffix string suffix, if present, shall be removed. This
shall be done by performing actions equivalent to the following
steps in order:
1. If string is a null string, it is unspecified whether the
resulting string is '.' or a null string. In either case,
skip steps 2 through 6.
2. If string is "//", it is implementation-defined whether steps
3 to 6 are skipped or processed.
3. If string consists entirely of <slash> characters, string
shall be set to a single <slash> character. In this case,
skip steps 4 to 6.
4. If there are any trailing <slash> characters in string, they
shall be removed.
5. If there are any <slash> characters remaining in string, the
prefix of string up to and including the last <slash>
character in string shall be removed.
6. If the suffix operand is present, is not identical to the
characters remaining in string, and is identical to a suffix
of the characters remaining in string, the suffix suffix
shall be removed from string. Otherwise, string is not
modified by this step. It shall not be considered an error if
suffix is not found in string.
The resulting string shall be written to standard output.
Параметры (Options)
None.
Операнды (Operands)
The following operands shall be supported:
string A string.
suffix 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
basename:
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 basename 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)
If the string string is a valid pathname:
$(basename -- "string")
produces a filename that could be used to open the file named by
string in the directory returned by:
$(dirname -- "string")
If the string string is not a valid pathname, the same algorithm
is used, but the result need not be a valid filename. The
basename utility is not expected to make any judgements about the
validity of string as a pathname; it just follows the specified
algorithm to produce a result string.
The following shell script compiles /usr/src/cmd/cat.c and moves
the output to a file named cat in the current directory when
invoked with the argument /usr/src/cmd/cat or with the argument
/usr/src/cmd/cat.c:
c99 -- "$(dirname -- "$1")/$(basename -- "$1" .c).c" &&
mv a.out "$(basename -- "$1" .c)"
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.
Обоснование (Rationale)
The behaviors of basename and dirname 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 early proposal versions of these
utilities due to the way it specified handling of trailing
<slash> characters.
Since the definition of pathname specifies implementation-defined
behavior for pathnames starting with two <slash> characters, this
volume of POSIX.1‐2017 specifies similar implementation-defined
behavior for the basename and dirname utilities.
Будущие направления (Future directions)
None.
Смотри также (See also)
Section 2.5, Parameters and Variables, dirname(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)
