1 files changed, 8 insertions, 5 deletions
diff --git a/sum4.awk b/sum4.awk
index aa3f044..3e61843 100644
--- a/sum4.awk
+++ b/sum4.awk
@@ -15,17 +15,19 @@ function isnum(n) {
 }
 
 
-BEGIN { OFS = FS }
+BEGIN {
+    OFS = FS
+}
+
 
 NR == 1 {
-    nf_max = NF
     for (i=1; i<=NF; i++)
         isnum($i) ? header[i] = "col" i : header[i] = $i
 }
 
-{
-    if (NF > nf_max)
-        nf_max = NF
+
+NF > 0 {
+    (NF > nf_max) ? nf_max = NF : nf_max = nf_max
     for (i=1; i<=NF; i++) {
         if ($i == header[i])
             continue
@@ -36,6 +38,7 @@ NR == 1 {
     }
 }
 
+
 END {
     for (i=1; i<=nf_max; i++) {
         printf((header[i]) ? header[i] OFS : OFS)