1readonly(1) User Commands readonly(1)
2
6 readonly - shell built-in function to protect the value of the given
7 variable from reassignment
8
10 sh
11 readonly [name]...
12 ksh
15 **readonly [name [= value]]...
16 **readonly -p
19 ksh93
22 ++readonly [-p] [name [= value]]...
23
26 sh
27 The given names are marked readonly and the values of the these names
28 may not be changed by subsequent assignment. If no arguments are given,
29 a list of all readonly names is printed.
30 ksh
32 The given names are marked readonly and these names cannot be changed
33 by subsequent assignment.
34 When -p is specified, readonly writes to the standard output the names
37 and values of all read-only variables, in the following format:
38 "readonly %s=%s\n", name, value
40 if name is set, and:
45 "readonly $s\n", name
47 if name is unset.
52 The shell formats the output, including the proper use of quoting, so
55 that it is suitable for reinput to the shell as commands that achieve
56 the same value and readonly attribute-setting results in a shell execu‐
57 tion environment in which:
58 1. Variables with values set at the time they were output do
60 not have the readonly attribute set.
61 2. Variables that were unset at the time they were output do
63 not have a value at the time at which the saved output is
64 re-input to the shell.
65 On this manual page, ksh(1) commands that are preceded by one or two **
68 (asterisks) are treated specially in the following ways:
69 1. Variable assignment lists preceding the command remain in
71 effect when the command completes.
72 2. I/O redirections are processed after variable assignments.
74 3. Errors cause a script that contains them to abort.
76 4. Words, following a command preceded by ** that are in the
78 format of a variable assignment, are expanded with the same
79 rules as a variable assignment. This means that tilde sub‐
80 stitution is performed after the = sign and word splitting
81 and file name generation are not performed.
82 ksh93
84 readonly sets the readonly attribute on each of the variables specified
85 by name which prevents their values from being changed. If =value is
86 specified, the variable name is set to value before the variable is
87 made readonly.
88 If no names are specified then the names and values of all readonly
91 variables are written to standard output.
92 readonly is built-in to the shell as a declaration command so that
95 field splitting and pathname expansion are not performed on the argu‐
96 ments. Tilde expansion occurs on value.
97 -p Causes the output to be in a form of readonly commands that can
99 be used as input to the shell to recreate the current set of
100 readonly variables.
101 On this manual page, ksh93(1) commands that are preceded by one or two
105 + symbols are treated specially in the following ways:
106 1. Variable assignment lists preceding the command remain in
108 effect when the command completes.
109 2. I/O redirections are processed after variable assignments.
111 3. Errors cause a script that contains them to abort.
113 4. They are not valid function names.
115 5. Words, following a command preceded by ++ that are in the
117 format of a variable assignment, are expanded with the same
118 rules as a variable assignment. This means that tilde sub‐
119 stitution is performed after the = sign and field splitting
120 and file name generation are not performed.
121
123 ksh93
124 The following exit values are returned:
125 0 Successful completion.
127 >0 An error occurred.
130
133 See attributes(5) for descriptions of the following attributes:
134 ┌─────────────────────────────┬─────────────────────────────┐
139 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
140 ├─────────────────────────────┼─────────────────────────────┤
141 │Availability │SUNWcsu │
142 └─────────────────────────────┴─────────────────────────────┘
143
145 ksh(1), ksh93(1), sh(1), typeset(1), attributes(5)
146SunOS 5.11 2 Nov 2007 readonly(1)