diff --git a/cheatsheets/find b/cheatsheets/find
index c6126b3..5cd262f 100644
--- a/cheatsheets/find
+++ b/cheatsheets/find
@@ -39,3 +39,6 @@ find . -maxdepth 2 -name build -type d
 
 # To search all files who are not in .git directory
 find . ! -iwholename '*.git*' -type f
+
+# Find all files that have the same node (hard link) as MY_FILE_HERE
+find / -type f -samefile MY_FILE_HERE 2>/dev/null
diff --git a/cheatsheets/iptables b/cheatsheets/iptables
index badc271..2e0a132 100644
--- a/cheatsheets/iptables
+++ b/cheatsheets/iptables
@@ -16,3 +16,25 @@ iptables -A INPUT -i eth0 -p tcp --dport 902 -j REJECT --reject-with icmp-port-u
 #	icmp-host-prohibited or
 #	icmp-admin-prohibited
 #	tcp-reset
+
+# Add a comment to a rule:
+iptables ... -m comment --comment "This rule is here for this reason"
+
+
+# To remove or insert a rule:
+# 1) Show all rules
+iptables -L INPUT --line-numbers
+# OR iptables -nL --line-numbers
+
+# Chain INPUT (policy ACCEPT)
+#     num  target prot opt source destination
+#     1    ACCEPT     udp  --  anywhere  anywhere             udp dpt:domain
+#     2    ACCEPT     tcp  --  anywhere  anywhere             tcp dpt:domain
+#     3    ACCEPT     udp  --  anywhere  anywhere             udp dpt:bootps
+#     4    ACCEPT     tcp  --  anywhere  anywhere             tcp dpt:bootps
+
+# 2.a) REMOVE (-D) a rule. (here an INPUT rule)
+iptables -D INPUT 2
+
+# 2.b) OR INSERT a rule.
+iptables -I INPUT {LINE_NUMBER} -i eth1 -p tcp --dport 21 -s 123.123.123.123 -j ACCEPT -m comment --comment "This rule is here for this reason"
diff --git a/cheatsheets/nmap b/cheatsheets/nmap
index 68da56a..afa46ef 100644
--- a/cheatsheets/nmap
+++ b/cheatsheets/nmap
@@ -34,3 +34,21 @@ nmap -traceroute [target]
 
 # Example: Ping scan all machines on a class C network
 nmap -sP 192.168.0.0/24
+
+# Use some script:
+nmap --script default,safe
+
+# Loads the script in the default category, the banner script, and all .nse files in the directory /home/user/customscripts.
+nmap --script default,banner,/home/user/customscripts
+
+# Loads all scripts whose name starts with http-, such as http-auth and http-open-proxy.
+nmap --script 'http-*'
+
+# Loads every script except for those in the intrusive category.
+nmap --script "not intrusive"
+
+# Loads those scripts that are in both the default and safe categories.
+nmap --script "default and safe"
+
+# Loads scripts in the default, safe, or intrusive categories, except for those whose names start with http-.
+nmap --script "(default or safe or intrusive) and not http-*"