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
12 alias - define or display aliases
13
15 alias [alias-name[=string] ...]
16
18 The alias utility shall create or redefine alias definitions or write
19 the values of existing alias definitions to standard output. An alias
20 definition provides a string value that shall replace a command name
21 when it is encountered; see Alias Substitution .
22 An alias definition shall affect the current shell execution environ‐
24 ment and the execution environments of the subshells of the current
25 shell. When used as specified by this volume of IEEE Std 1003.1-2001,
26 the alias definition shall not affect the parent process of the current
27 shell nor any utility environment invoked by the shell; see Shell Exe‐
28 cution Environment .
29
31 None.
32
34 The following operands shall be supported:
35 alias-name
37 Write the alias definition to standard output.
38 alias-name=string
40 Assign the value of string to the alias alias-name.
42 If no operands are given, all alias definitions shall be written to
45 standard output.
46
48 Not used.
49
51 None.
52
54 The following environment variables shall affect the execution of
55 alias:
56 LANG Provide a default value for the internationalization variables
58 that are unset or null. (See the Base Definitions volume of
59 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
60 ables for the precedence of internationalization variables used
61 to determine the values of locale categories.)
62 LC_ALL If set to a non-empty string value, override the values of all
64 the other internationalization variables.
65 LC_CTYPE
67 Determine the locale for the interpretation of sequences of
68 bytes of text data as characters (for example, single-byte as
69 opposed to multi-byte characters in arguments).
70 LC_MESSAGES
72 Determine the locale that should be used to affect the format
73 and contents of diagnostic messages written to standard error.
74 NLSPATH
76 Determine the location of message catalogs for the processing of
77 LC_MESSAGES .
78
81 Default.
82
84 The format for displaying aliases (when no operands or only name oper‐
85 ands are specified) shall be:
86 "%s=%s\n", name, value
89 The value string shall be written with appropriate quoting so that it
91 is suitable for reinput to the shell. See the description of shell
92 quoting in Quoting .
93
95 The standard error shall be used only for diagnostic messages.
96
98 None.
99
101 None.
102
104 The following exit values shall be returned:
105 0 Successful completion.
107 >0 One of the name operands specified did not have an alias defini‐
109 tion, or an error occurred.
110
113 Default.
114 The following sections are informative.
116
118 None.
119
121 1. Change ls to give a columnated, more annotated output:
122 alias ls="ls -CF"
125 2. Create a simple "redo" command to repeat previous entries in the
127 command history file:
128 alias r='fc -s'
131 3. Use 1K units for du:
133 alias du=du\ -k
136 4. Set up nohup so that it can deal with an argument that is itself an
138 alias name:
139 alias nohup="nohup "
142
144 The alias description is based on historical KornShell implementations.
145 Known differences exist between that and the C shell. The KornShell
146 version was adopted to be consistent with all the other KornShell fea‐
147 tures in this volume of IEEE Std 1003.1-2001, such as command line
148 editing.
149 Since alias affects the current shell execution environment, it is gen‐
151 erally provided as a shell regular built-in.
152 Historical versions of the KornShell have allowed aliases to be
154 exported to scripts that are invoked by the same shell. This is trig‐
155 gered by the alias -x flag; it is allowed by this volume of
156 IEEE Std 1003.1-2001 only when an explicit extension such as -x is
157 used. The standard developers considered that aliases were of use pri‐
158 marily to interactive users and that they should normally not affect
159 shell scripts called by those users; functions are available to such
160 scripts.
161 Historical versions of the KornShell had not written aliases in a
163 quoted manner suitable for reentry to the shell, but this volume of
164 IEEE Std 1003.1-2001 has made this a requirement for all similar out‐
165 put. Therefore, consistency with this volume of IEEE Std 1003.1-2001
166 was chosen over this detail of historical practice.
167
169 None.
170
172 Function Definition Command
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175 Portions of this text are reprinted and reproduced in electronic form
176 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
177 -- Portable Operating System Interface (POSIX), The Open Group Base
178 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
179 Electrical and Electronics Engineers, Inc and The Open Group. In the
180 event of any discrepancy between this version and the original IEEE and
181 The Open Group Standard, the original IEEE and The Open Group Standard
182 is the referee document. The original Standard can be obtained online
183 at http://www.opengroup.org/unix/online.html .
184IEEE/The Open Group 2003 ALIAS(1P)