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46 lines
1.1 KiB
Markdown
46 lines
1.1 KiB
Markdown
# The readonly builtin command
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## Synopsis
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readonly [-p] [-a] [-A] [-f] [NAME[=VALUE] ...]
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## Description
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The `readonly` builtin command is used to mark variables or functions as
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read-only, which means unchangeable. This implies that it can't be
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unset anymore. A `readonly` variable may not be redefined in child
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scopes. A readonly global may not be redefined as a function local
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variable. Simple command environment assignments may not reference
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readonly variables.
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### Options
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|Option|Description|
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|-|-|
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|`-a`|refer to normal arrays|
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|`-A`|refer to associative arrays|
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|`-f`|refer to functions|
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|`-p`|print all read-only variables or functions, `-a`, `-A` and `-f` can be used to filter. The output is reusable as input|
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An argument of `--` disables further option processing.
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### Return status
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|Status|Reason|
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|-|-|
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|0|no error|
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|!=0|invalid option|
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|!=0|invalid combination of options|
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|!=0|a given `NAME` is invalid|
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## Examples
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## Portability considerations
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- in POSIX(r), only the `-p` option is specified
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## See also
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- [declare](../../commands/builtin/declare.md)
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- [unset](../../commands/builtin/unset.md)
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