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Unlike in other shells, for-loops do not set $status if 1. the loop count is zero, or if 2. the loop body consists of only commands like "set" that don't set $status. POSIX for-loops always set an exit status (they set 0 if no loop iterations). Following that would be awkward because it would add a lot of complexity in combination with the 2 special cases above. Document that "for" behaves the same as "set": it will pass through existing $status, and also the last child's $status. See the discussion in #8409
53 lines
1.5 KiB
ReStructuredText
53 lines
1.5 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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::
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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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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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