[PATCH] join: new applet

[mjmouse9999 at gmail.com]

From: busybox <busybox-bounces at busybox.net> On Behalf Of Ron Yorston via
busybox
Sent: Monday, 6 July 2026 00:56
> [...]
>
> +	n = 0;
> +	if (sep != '\0') {  /* single-character split */
> +		while ((s1 = strchr(ps, sep)) != NULL) {
> +			sl[n] = ps;
> +			*s1 = '\0';
> +			ps = s1 + 1;
> +			n++;
> +		}
> +		/* Add the last field */
> +		sl[n] = ps;
> +		n++;
> +		curr->fieldcount = n;

Looks like I missed a return here to stop re-parsing when reworking that
function:

+		return;

> +	}
> +	/* default split: skip the initial whitespace and then any run
> +	   of non-whitespace characters is a field */
>
> [...]
>
> +
> +testing "join -o for fields to print, -e for empty fields" \
> +	"join -a 1 -a 2 -e --- -o 0,1.2,2.2 input -" \
> +	"a 123 abc\nb 456 ---\nc 789 def\nd --- ghi\n" \
> +	"a 123\nb 456\nc 789\n" \
> +	"a abc\nc def\nd ghi\n"
> +
> +testing "join -o works for combinatorial" \
> +	"join -o 0,1.2,2.2 input -" \
> +	"a 123 abc\na 123 def\na 456 abc\na 456 def\n" \
> +	"a 123\na 456\n" \
> +	"a abc\na def\n"

And so we can add this test:

+testing "join -t works" \
+	"join -t A input -" \
+	"item 1A123Aabc\nitem 2A456Adef\n" \
+	"item 1A123\nitem 2A456\n" \
+	"item 1Aabc\nitem 2Adef\n"

> +
> +exit $FAILCOUNT
> --
> 2.55.0
>
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