определить или отобразить псевдонимы (define or display aliases)
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)
alias — define or display aliases
Синопсис (Synopsis)
alias [alias-name[=string]...]
Описание (Description)
The alias utility shall create or redefine alias definitions or
write the values of existing alias definitions to standard
output. An alias definition provides a string value that shall
replace a command name when it is encountered; see Section 2.3.1,
Alias Substitution.
An alias definition shall affect the current shell execution
environment and the execution environments of the subshells of
the current shell. When used as specified by this volume of
POSIX.1‐2017, the alias definition shall not affect the parent
process of the current shell nor any utility environment invoked
by the shell; see Section 2.12, Shell Execution Environment.
Параметры (Options)
None.
Операнды (Operands)
The following operands shall be supported:
alias-name
Write the alias definition to standard output.
alias-name=string
Assign the value of string to the alias alias-name.
If no operands are given, all alias definitions shall be written
to standard output.
Стандартный ввод (Stdin)
Not used.
Входные файлы (Input files)
None.
Переменные окружения (Environment variables)
The following environment variables shall affect the execution of
alias:
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 format for displaying aliases (when no operands or only name
operands are specified) shall be:
"%s=%s\n", name, value
The value string shall be written with appropriate quoting so
that it is suitable for reinput to the shell. See the description
of shell quoting in Section 2.2, Quoting.
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 One of the name operands specified did not have an alias
definition, or an error occurred.
Последствия ошибок (Consequences of errors)
Default.
The following sections are informative.
Использование в приложениях (Application usage)
None.
Примеры (Examples)
1. Create a short alias for a commonly used ls command:
alias lf="ls -CF"
2. Create a simple ``redo'' command to repeat previous entries
in the command history file:
alias r='fc -s'
3. Use 1K units for du:
alias du=du\ -k
4. Set up nohup so that it can deal with an argument that is
itself an alias name:
alias nohup="nohup "
Обоснование (Rationale)
The alias description is based on historical KornShell
implementations. Known differences exist between that and the C
shell. The KornShell version was adopted to be consistent with
all the other KornShell features in this volume of POSIX.1‐2017,
such as command line editing.
Since alias affects the current shell execution environment, it
is generally provided as a shell regular built-in.
Historical versions of the KornShell have allowed aliases to be
exported to scripts that are invoked by the same shell. This is
triggered by the alias -x flag; it is allowed by this volume of
POSIX.1‐2017 only when an explicit extension such as -x is used.
The standard developers considered that aliases were of use
primarily to interactive users and that they should normally not
affect shell scripts called by those users; functions are
available to such scripts.
Historical versions of the KornShell had not written aliases in a
quoted manner suitable for reentry to the shell, but this volume
of POSIX.1‐2017 has made this a requirement for all similar
output. Therefore, consistency was chosen over this detail of
historical practice.
Будущие направления (Future directions)
None.
Смотри также (See also)
Section 2.9.5, Function Definition Command
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables
