1ALIAS(1P) POSIX Programmer's Manual ALIAS(1P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
13 alias — define or display aliases
14
16 alias [alias-name[=string]...]
17
19 The alias utility shall create or redefine alias definitions or write
20 the values of existing alias definitions to standard output. An alias
21 definition provides a string value that shall replace a command name
22 when it is encountered; see Section 2.3.1, Alias Substitution.
23 An alias definition shall affect the current shell execution environ‐
25 ment and the execution environments of the subshells of the current
26 shell. When used as specified by this volume of POSIX.1‐2008, the alias
27 definition shall not affect the parent process of the current shell nor
28 any utility environment invoked by the shell; see Section 2.12, Shell
29 Execution Environment.
30
32 None.
33
35 The following operands shall be supported:
36 alias-name
38 Write the alias definition to standard output.
39 alias-name=string
41 Assign the value of string to the alias alias-name.
42 If no operands are given, all alias definitions shall be written to
44 standard output.
45
47 Not used.
48
50 None.
51
53 The following environment variables shall affect the execution of
54 alias:
55 LANG Provide a default value for the internationalization vari‐
57 ables that are unset or null. (See the Base Definitions vol‐
58 ume of POSIX.1‐2008, Section 8.2, Internationalization Vari‐
59 ables for the precedence of internationalization variables
60 used to determine the values of locale categories.)
61 LC_ALL If set to a non-empty string value, override the values of
63 all the other internationalization variables.
64 LC_CTYPE Determine the locale for the interpretation of sequences of
66 bytes of text data as characters (for example, single-byte as
67 opposed to multi-byte characters in arguments).
68 LC_MESSAGES
70 Determine the locale that should be used to affect the format
71 and contents of diagnostic messages written to standard
72 error.
73 NLSPATH Determine the location of message catalogs for the processing
75 of LC_MESSAGES.
76
78 Default.
79
81 The format for displaying aliases (when no operands or only name oper‐
82 ands are specified) shall be:
83 "%s=%s\n", name, value
85 The value string shall be written with appropriate quoting so that it
87 is suitable for reinput to the shell. See the description of shell
88 quoting in Section 2.2, Quoting.
89
91 The standard error shall be used only for diagnostic messages.
92
94 None.
95
97 None.
98
100 The following exit values shall be returned:
101 0 Successful completion.
103 >0 One of the name operands specified did not have an alias defini‐
105 tion, or an error occurred.
106
108 Default.
109 The following sections are informative.
111
113 None.
114
116 1. Create a short alias for a commonly used ls command:
117 alias lf="ls −CF"
119 2. Create a simple ``redo'' command to repeat previous entries in the
121 command history file:
122 alias r='fc −s'
124 3. Use 1K units for du:
126 alias du=du\ −k
128 4. Set up nohup so that it can deal with an argument that is itself an
130 alias name:
131 alias nohup="nohup "
133
135 The alias description is based on historical KornShell implementations.
136 Known differences exist between that and the C shell. The KornShell
137 version was adopted to be consistent with all the other KornShell fea‐
138 tures in this volume of POSIX.1‐2008, such as command line editing.
139 Since alias affects the current shell execution environment, it is gen‐
141 erally provided as a shell regular built-in.
142 Historical versions of the KornShell have allowed aliases to be
144 exported to scripts that are invoked by the same shell. This is trig‐
145 gered by the alias −x flag; it is allowed by this volume of
146 POSIX.1‐2008 only when an explicit extension such as −x is used. The
147 standard developers considered that aliases were of use primarily to
148 interactive users and that they should normally not affect shell
149 scripts called by those users; functions are available to such scripts.
150 Historical versions of the KornShell had not written aliases in a
152 quoted manner suitable for reentry to the shell, but this volume of
153 POSIX.1‐2008 has made this a requirement for all similar output. There‐
154 fore, consistency was chosen over this detail of historical practice.
155
157 None.
158
160 Section 2.9.5, Function Definition Command
161 The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
163 Variables
164
166 Portions of this text are reprinted and reproduced in electronic form
167 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
168 -- Portable Operating System Interface (POSIX), The Open Group Base
169 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
170 cal and Electronics Engineers, Inc and The Open Group. (This is
171 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
172 event of any discrepancy between this version and the original IEEE and
173 The Open Group Standard, the original IEEE and The Open Group Standard
174 is the referee document. The original Standard can be obtained online
175 at http://www.unix.org/online.html .
176 Any typographical or formatting errors that appear in this page are
178 most likely to have been introduced during the conversion of the source
179 files to man page format. To report such errors, see https://www.ker‐
180 nel.org/doc/man-pages/reporting_bugs.html .
181IEEE/The Open Group 2013 ALIAS(1P)