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39 lines
1.1 KiB
Markdown
39 lines
1.1 KiB
Markdown
# Link A Scalar To An Array
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`Zsh` has a builtin command `typeset` that does a variety of things. When given
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the `-T` flag and the names of a scalar and an array, it will link them
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together so that a change to one is reflected in the other.
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The scalar is a string of values delimited by a colon (`:`). The array is an
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array that can be interacted with using array operations like append (`+=`).
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```bash
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$ typeset -T FOO foo
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$ echo $FOO
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$ export FOO="one:two"
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$ echo $foo
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one two
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$ foo+=three
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$ echo $FOO
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one:two:three
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```
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Notice `FOO` is initially empty. I then `export` it to overwrite it with two
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values delimited by a colon. Since `foo` is automatically kept in sync, I can
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`echo $foo` and see those values displayed as an array. I can then append a
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third value using an array operation on `foo`. The update will be automatically
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reflected in `FOO`.
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`Zsh` does this under the hood for `PATH` and `path` which is why you can [add
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to the path via the path array](add-to-the-path-via-path-array.md).
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See `man zshbuiltins` for more details.
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[source](http://devlib.symbian.slions.net/s3/GUID-D87C96CE-3F23-552D-927C-B6A1D61691BF.html)
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