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45 lines
1.6 KiB
Markdown
45 lines
1.6 KiB
Markdown
# The local builtin command
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## Synopsis
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local [option] name[=value] ...
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## Description
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`local` is identical to [declare](/commands/builtin/declare.md) in every
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way, and takes all the same options, with two exceptions:
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- Usage outside of a function is an error. Both `declare` and `local`
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within a function have the same effect on variable scope, including
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the -g option.
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- `local` with no options prints variable names and values in the same
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format as `declare` with no options, except the variables are filtered
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to print only locals that were set in the same scope from which
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`local` was called. Variables in parent scopes are not printed.
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## Portability considerations
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- `local` is not specified by POSIX. Most bourne-like shells don't have
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a builtin called `local`, but some such as `dash` and the busybox
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shell do.
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<!-- -->
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- The behavior of function scope is not defined by POSIX, however local
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variables are implemented widely by bourne-like shells, and behavior
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differs substantially. Even the`dash` shell has local variables.
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<!-- -->
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- In ksh93, using POSIX-style function definitions, `typeset` doesn't
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set `local` variables, but rather acts upon variables of the
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next-outermost scope (e.g. setting attributes). Using `typeset` within
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functions defined using ksh `function name {` syntax, variables follow
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roughly
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[lexical-scoping](http://community.schemewiki.org/?lexical-scope),
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except that functions themselves don't have scope, just like Bash.
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This means that even functions defined within a "function's scope"
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don't have access to non-local variables except through `namerefs`.
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## See also
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