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3a23fdf359
Includes harmonizing the display of options and arguments, standardising terminology, using the envvar directive more broadly, adding help options to all commands that support them, simplifying some language, and tidying up multiple formatting issues. string documentation is not changed.
51 lines
1.6 KiB
ReStructuredText
51 lines
1.6 KiB
ReStructuredText
.. _cmd-for:
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for - perform a set of commands multiple times
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==============================================
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Synopsis
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--------
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.. synopsis::
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for VARNAME in [VALUES ...]; COMMANDS ...; end
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Description
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-----------
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**for** is a loop construct. It will perform the commands specified by *COMMANDS* multiple times. On each iteration, the local variable specified by *VARNAME* is assigned a new value from *VALUES*. If *VALUES* is empty, *COMMANDS* will not be executed at all. The *VARNAME* is visible when the loop terminates and will contain the last value assigned to it. If *VARNAME* does not already exist it will be set in the local scope. For our purposes if the **for** block is inside a function there must be a local variable with the same name. If the **for** block is not nested inside a function then global and universal variables of the same name will be used if they exist.
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Much like :ref:`set <cmd-set>`, **for** does not modify $status, but the evaluation of its subordinate commands can.
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The **-h** or **--help** option displays help about using this command.
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Example
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-------
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::
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for i in foo bar baz; echo $i; end
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# would output:
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foo
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bar
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baz
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Notes
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-----
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The ``VARNAME`` was local to the for block in releases prior to 3.0.0. This means that if you did something like this:
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::
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for var in a b c
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if break_from_loop
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break
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end
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end
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echo $var
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The last value assigned to ``var`` when the loop terminated would not be available outside the loop. What ``echo $var`` would write depended on what it was set to before the loop was run. Likely nothing.
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