added the host file plugin

plugins/available/hosts.plugin.bash

@@ -0,0 +1,90 @@
+#!/bin/bash
+
+# cite about-plugin
+# about-plugin '/etc/hosts based operations'
+
+FILE="/etc/hosts"
+
+function hosts_add {
+    local ENTRY=`grep "$2" $FILE`
+    if  [[ $ENTRY != "" ]]
+    then
+        echo "Host "$2" already added"
+        echo $ENTRY
+    else
+        echo "$1 $2" | sudo tee -a /etc/hosts > /dev/null
+        echo "Added $1 $2 to hosts file"
+        exit 1
+    fi
+}
+
+function hosts_list {
+    cat $FILE
+}
+
+function hosts_remove {
+    local ENTRY=`grep "$1" $FILE`
+    if  [[ $ENTRY != "" ]]
+    then
+        DELETED=`grep -w -v $1 $FILE`
+        echo "$DELETED" | sudo tee /etc/hosts > /dev/null
+        echo "Removed \""$ENTRY"\" from hosts file"
+    else
+        echo "Host "$1" not found"
+        exit 1
+    fi
+}
+
+function help {
+    echo -e "usage: hosts [add|list|remove] ip_address host_name"
+    echo
+    echo -e  "commands:"
+    echo -e "\tadd\tMaps the hostname with ip and adds it to $FILE"
+    echo -e "\tlist\tList all the hostname and ip in $FILE"
+    echo -e "\tremove\tRemoved the entry from $FILE based on host_name"
+    echo
+    echo -e "examples:"
+    echo -e "\t$ host add 127.0.0.1 my_localhost"
+    
+}
+
+# the validator function
+function validate {
+    if [[ $1 == "" || $2 == "" ]]
+    then
+        return 0;
+    else
+        return 1;
+    fi
+}
+
+
+# entry point
+case $1 in
+    "add")
+        validate $2 $3
+        if [[ $? == 0 ]]
+        then
+            help
+            exit 1
+        else
+            hosts_add $2 $3
+        fi
+    ;;
+    "list")
+        hosts_list
+    ;;
+    "remove")
+        validate $2 "dummy" # sending dummy to verify only one argument
+        if [[ $? == 0 ]]
+        then
+            help
+            exit 1
+        else
+            hosts_remove $2
+        fi
+    ;;
+    *)
+        help
+    ;;
+esac