1 files changed, 6 insertions, 4 deletions

diff --git a/diff.awk b/diff.awk
index bf8b472..83fd0b5 100644
--- a/diff.awk
+++ b/diff.awk
@@ -3,9 +3,9 @@
 ### diff.awk
 # print numerical diff along columns
 
+
 BEGIN {
     OFS = FS
-    # OFMT = "%.9g"
     sign = "[+-]?"
     decimal = "[0-9]+[.]?[0-9]*"
     fraction = "[.][0-9]*"
@@ -13,6 +13,8 @@ BEGIN {
     number = "^" sign "(" decimal "|" fraction ")" exponent "$"
 }
 
+
+# column headers
 NR == 1 {
     # orig data columns
     for (n=1; n<=NF; n++) {
@@ -35,9 +37,9 @@ NR == 1 {
     }
 }
 
-NF {
-    if (NF > nf_max)
-        nf_max = NF
+
+NF > 0 {
+    (NF > nf_max) ? nf_max = NF : nf_max = nf_max
 
     # data columns
     for (n=1; n<=nf_max; n++) {