Revise deduplicate util to not reorder lines in

the input sequence. This is important to preserve integrity of the
original input data.

By comparison, the sort order doesn't matter when we do frequencies.

Author: adityaathalye

log-analysis.sh

@@ -20,7 +20,17 @@ ensure_deps "gawk" "jq"
 # ####################
 
 deduplicate() {
-    sort | uniq
+    # Ref. technique as seen here: https://stackoverflow.com/a/20639730
+    # Or use awk '!x[$0]++', as seen here https://stackoverflow.com/a/11532197
+
+    # print stdin stream with line-number prefixed
+    cat -n |
+        # sort uniquely by second key (the incoming lines)
+        sort -uk2 |
+        # sort numeric by first key (line number)
+        sort -nk1 |
+        # select second field to the end
+        cut -f2-
 }
 
 frequencies() {