Allow to specify size in terabytes by using T or t suffix.

This speeds up my testing a bit. Because truncate(1) doesn't allocate
blocks on file system before they are used, it is very useful to
emulate huge file systems:

	# truncate -s 16T fs.img
	# mdconfig -a -f fs.img
	# newfs /dev/mdX

(-t swap can be used as well)

usr.bin/truncate/truncate.1

@@ -39,7 +39,7 @@
 .Sm off
 .Op Cm + | -
 .Ar size
-.Op Cm K | k | M | m | G | g
+.Op Cm K | k | M | m | G | g | T | t
 .Sm on
 .Xc
 .Ek
@@ -71,7 +71,7 @@ Truncate files to the length of the file
 .Sm off
 .Op Cm + | -
 .Ar size
-.Op Cm K | k | M | m | G | g
+.Op Cm K | k | M | m | G | g | T | t
 .Sm on
 .Xc
 If the
@@ -94,11 +94,12 @@ The
 .Ar size
 argument may be suffixed with one of
 .Cm K ,
-.Cm M
-or
+.Cm M ,
 .Cm G
+or
+.Cm T
 (either upper or lower case) to indicate a multiple of
-Kilobytes, Megabytes or Gigabytes
+Kilobytes, Megabytes, Gigabytes or Terabytes
 respectively.
 .El
 .Pp

usr.bin/truncate/truncate.c

@@ -176,6 +176,10 @@ parselength(char *ls, off_t *sz)
 	}
 
 	switch (*ls) {
+	case 'T':
+	case 't':
+		oflow = length * 1024;
+		ASSIGN_CHK_OFLOW(oflow, length);
 	case 'G':
 	case 'g':
 		oflow = length * 1024;