NEW: Added if-usage.sh showing various use of the if statement

sh/if-usage.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+if ls -d /tmp; then
+  echo "Command succeeded: file exists."
+fi
+
+if [ -f /etc/hosts ]; then
+	echo "/etc/hosts exists"
+fi
+
+num=100
+if [ "$num" -gt 10 ]; then
+  echo "The number is greater than 10."
+fi
+
+floatnum=20.34
+result=$(echo "$floatnum > 10.5" | bc)
+if [ "$result" -eq 1 ]; then
+  echo "The number is greater than 10.5"
+fi
+
+word="hello"
+if [ "$word" = "hello" ]; then
+  echo "You typed hello."
+fi
+
+sentense="I want to say hello to the world"
+regex="say.*hello"
+if [[ "$sentense" =~ $regex ]]; then
+  echo "Substring found."
+fi