Apparently, the One True awk had some features in it that Plan 9 awk did not:

	length(array) returns the number of subscripts in array
	fflush() or fflush("") flushes all open files

I added them back in, and updated the manual page.

- Pietro

Reference: /n/sources/patch/applied/one-true-awk-adjust
Date: Thu Jul  3 15:48:01 CES 2008
Signed-off-by: pietro10@mac.com

--- /sys/src/cmd/awk/run.c	Thu Jul  3 15:46:56 2008
+++ /sys/src/cmd/awk/run.c	Thu Jul  3 15:46:53 2008
@@ -1454,14 +1454,20 @@
 	char mbc[50];
 	Node *nextarg;
 	FILE *fp;
+	void flush_all(void);
 
 	t = ptoi(a[0]);
 	x = execute(a[1]);
 	nextarg = a[1]->nnext;
 	switch (t) {
 	case FLENGTH:
-		p = getsval(x);
-		u = (Awkfloat) countposn(p, strlen(p)); break;
+		if (isarr(x))
+			u = ((Array *) x->sval)->nelem;	/* GROT. should be function*/
+		else {
+			p = getsval(x);
+			u = (Awkfloat) countposn(p, strlen(p));
+		}
+		break;
 	case FLOG:
 		u = errcheck(log(getfval(x)), "log"); break;
 	case FINT:
@@ -1518,7 +1524,10 @@
 		free(buf);
 		return x;
 	case FFLUSH:
-		if ((fp = openfile(FFLUSH, getsval(x))) == NULL)
+		if (isrec(x) || strlen(getsval(x)) == 0) {
+			flush_all();	/* fflush() or fflush("") -> all */
+			u = 0;
+		} else if ((fp = openfile(FFLUSH, getsval(x))) == NULL)
 			u = EOF;
 		else
 			u = fflush(fp);
@@ -1711,6 +1720,15 @@
 			if (stat == EOF)
 				WARNING( "i/o error occurred while closing %s", files[i].fname );
 		}
+}
+
+void flush_all(void)
+{
+	int i;
+
+	for (i = 0; i < FOPEN_MAX; i++)
+		if (files[i].fp)
+			fflush(files[i].fp);
 }
 
 void backsub(char **pb_ptr, char **sptr_ptr);
--- /sys/man/1/awk	Thu Jul  3 15:46:58 2008
+++ /sys/man/1/awk	Thu Jul  3 15:46:57 2008
@@ -204,6 +204,9 @@
 .BI fflush( expr )
 flushes any buffered output for the file or pipe
 .IR expr .
+If
+.IR expr
+is omitted or is a null string, all open files are flushed.
 .PP
 The mathematical functions
 .BR exp ,
@@ -218,11 +221,11 @@
 .TF length
 .TP
 .B length
-the length of its argument
-taken as a string,
-or of
+If its argument is a string, the string's length is returned.
+If its argument is an array, the number of subscripts in the array is returned.
+If no argument, the length of
 .B $0
-if no argument.
+is returned.
 .TP
 .B rand
 random number on (0,1)