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0e1f5108ae
* string: Allow `collect --no-empty` to avoid empty ellision
Currently we still have that issue where
test -n (thing | string collect)
can return true if `thing` doesn't print anything, because the
collected argument will still be removed.
So, what we do is allow `--no-empty` to be used, in which case we
print one empty argument.
This means
test -n (thing | string collect -n)
can now be safely used.
"no-empty" isn't the best name for this flag, but string's design
really incentivizes reusing names, and it's not *terrible*.
* Switch to `--allow-empty`
`--no-empty` does the exact opposite for `string split` and split0.
Since `-a`/`--allow-empty` already exists, use it.
51 lines
1.5 KiB
ReStructuredText
51 lines
1.5 KiB
ReStructuredText
string-collect - join strings into one
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======================================
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Synopsis
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--------
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.. BEGIN SYNOPSIS
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::
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string collect [(-a | --allow-empty)] [(-N | --no-trim-newlines)] [STRING...]
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.. END SYNOPSIS
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Description
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-----------
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.. BEGIN DESCRIPTION
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``string collect`` collects its input into a single output argument, without splitting the output when used in a command substitution. This is useful when trying to collect multiline output from another command into a variable. Exit status: 0 if any output argument is non-empty, or 1 otherwise.
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If invoked with multiple arguments instead of input, ``string collect`` preserves each argument separately, where the number of output arguments is equal to the number of arguments given to ``string collect``.
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Any trailing newlines on the input are trimmed, just as with ``"$(cmd)"`` substitution in sh. ``--no-trim-newlines`` can be used to disable this behavior, which may be useful when running a command such as ``set contents (cat filename | string collect -N)``.
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With ``--allow-empty``, ``string collect`` always prints one (empty) argument. This can be used to prevent an argument from disappearing.
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.. END DESCRIPTION
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Examples
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--------
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.. BEGIN EXAMPLES
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::
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>_ echo \"(echo one\ntwo\nthree | string collect)\"
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"one
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two
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three"
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>_ echo \"(echo one\ntwo\nthree | string collect -N)\"
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"one
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two
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three
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"
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>_ echo foo(true | string collect --allow-empty)bar
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foobar
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.. END EXAMPLES
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