fish-shell/doc_src/cmds/for.rst
Fabian Boehm 38b24c2325 docs: Use :doc: role when linking to commands
This makes it so we link to the very top of the document instead of a
special anchor we manually include.

So clicking e.g. :doc:`string <cmds/string>` will link you to
cmds/string.html instead of cmds/string.html#cmd-string.

I would love to have a way to say "this document from the root of the
document path", but that doesn't appear to work, I tried
`/cmds/string`.

So we'll just have to use cmds/string in normal documents and plain
`string` from other commands.
2022-09-24 10:56:43 +02:00

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.. _cmd-for:
for - perform a set of commands multiple times
==============================================
Synopsis
--------
.. synopsis::
for VARNAME in [VALUES ...]; COMMANDS ...; end
Description
-----------
**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.
Much like :doc:`set <set>`, **for** does not modify $status, but the evaluation of its subordinate commands can.
The **-h** or **--help** option displays help about using this command.
Example
-------
::
for i in foo bar baz; echo $i; end
# would output:
foo
bar
baz
Notes
-----
The ``VARNAME`` was local to the for block in releases prior to 3.0.0. This means that if you did something like this:
::
for var in a b c
if break_from_loop
break
end
end
echo $var
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.