Originální popis anglicky:
alias - define or display aliases
Návod, kniha: POSIX Programmer's Manual
alias [alias-name[=string]
... ]
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
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 IEEE Std 1003.1-2001, the alias
definition shall not affect the parent process of the current shell nor any
utility environment invoked by the shell; see
Shell Execution
Environment .
None.
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.
Not used.
None.
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
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_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 .
Default.
The format for displaying aliases (when no operands or only
name operands
are specified) shall be:
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
Quoting .
The standard error shall be used only for diagnostic messages.
None.
None.
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.
Default.
The following sections are informative.
None.
- 1.
- Change ls to give a columnated, more annotated
output:
- 2.
- Create a simple "redo" command to repeat previous
entries in the command history file:
- 3.
- Use 1K units for du:
- 4.
- Set up nohup so that it can deal with an argument
that is itself an alias name:
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 IEEE Std 1003.1-2001, 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
IEEE Std 1003.1-2001 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
IEEE Std 1003.1-2001 has made this a requirement for all similar
output. Therefore, consistency with this volume of
IEEE Std 1003.1-2001 was chosen over this detail of historical
practice.
None.
Function Definition Command
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
.
