Differences

This shows you the differences between two versions of the page.

--- fuss:awk [2018/01/02 01:47] – [Convert Key-Value Map to JSON] office
+++ fuss:awk [2025/08/03 19:41] (current) – external edit 127.0.0.1
@@ Line 122: / Line 122: @@
 '
 </code>
+====== Netstat with Awk ======
+From [[https://gist.github.com/qistoph/1b0708c888f078c3720de6c6f9562997|qistoph]].
+<code bash>
+# Based on gist https://gist.github.com/staaldraad/4c4c80800ce15b6bef1c1186eaa8da9f
+# - added TCP states
+awk 'BEGIN{states["01"]="TCP_ESTABLISHED"
+states["02"]="TCP_SYN_SENT"
+states["03"]="TCP_SYN_RECV"
+states["04"]="TCP_FIN_WAIT1"
+states["05"]="TCP_FIN_WAIT2"
+states["06"]="TCP_TIME_WAIT"
+states["07"]="TCP_CLOSE"
+states["08"]="TCP_CLOSE_WAIT"
+states["09"]="TCP_LAST_ACK"
+states["0A"]="TCP_LISTEN"
+states["0B"]="TCP_CLOSING"
+states["0C"]="TCP_NEW_SYN_RECV"
+}
+function hextodec(str,ret,n,i,k,c){
+    ret = 0
+    n = length(str)
+    for (i = 1; i <= n; i++) {
+        c = tolower(substr(str, i, 1))
+        k = index("123456789abcdef", c)
+        ret = ret * 16 + k
+    }
+    return ret
+}
+function getIP(str,ret){
+    ret=hextodec(substr(str,index(str,":")-2,2));
+    for (i=5; i>0; i-=2) {
+        ret = ret"."hextodec(substr(str,i,2))
+    }
+    ret = ret":"hextodec(substr(str,index(str,":")+1,4))
+    return ret
+}
+NR > 1 {{if(NR==2)print "Local - Remote";local=getIP($2);remote=getIP($3)}{print local" - "remote" "states[$4]}}' /proc/net/tcp
+</code>
+====== Compute the Standard Deviation of a Column of Numbers ======
+From [[https://stackoverflow.com/questions/18786073/compute-average-and-standard-deviation-with-awk|the very question]] on how to compute [[/fuss/mathematics/probabilities_and_statistics|the standard deviation]]:
+<code bash>
+awk '{ x += $0; y += $0 ^ 2 } END { print sqrt( y/NR - (x/NR) ^ 2) }'
+</code>