1 files changed, 111 insertions, 0 deletions

diff --git a/bin/changedns b/bin/changedns
new file mode 100755
index 0000000..4760a67
--- a/dev/null
+++ b/bin/changedns
@@ -0,0 +1,111 @@
+#!/bin/bash
+
+        SN="`basename $0`"# base portion of our filename
+        AE="-a"                 # switch to add an entry
+        RE="-r"                 # swithc to remove an entry
+        EL="/tmp/resolv.conf"# expected location of the system nameserver config file
+        ARGS="$@"       # friendly variable name for all args
+
+usage(){
+        echo "usage:
+$SN -a {ip} [{ip}...]
+$SN -r {ip} [{ip}...]"
+}
+
+#if are there at least two arguments?
+if [ "$#" -gt 1 ]
+then
+
+        #remove any old resolv.conf file
+        rm .resolve.conf .resolve.old .resolve.new 2> /dev/null
+                        
+        #cast current nameserver file into OLD
+        cat "$EL" > .resolve.old
+
+        #build IP list
+        for ARG in $ARGS
+        do
+                if [ "$ARG" != "$1" ]
+                then
+                        IP_LIST=`echo "$IP_LIST $ARG"`
+                fi
+        done
+
+        #select case on first switch
+        case "$1" in
+
+                #case '-a'
+                        "$AE")
+
+                        #for each IP in IP_LIST
+                        for IP in $IP_LIST
+                        do
+                                #add nameserver entery to .newfile
+                                echo "nameserver $IP" >> .resolve.conf
+
+                                #cat OLD into grep excluding IP lines,
+                                #storing results into NEW
+                                cat .resolve.old | grep -v "$IP" > .resolve.new
+
+                                #set OLD to NEW
+                                cat .resolve.new > .resolve.old
+
+                        done
+
+                        #cat OLD onto end of .newfile
+                        cat .resolve.new >> .resolve.conf
+
+                        #clean up work files
+                        rm .resolve.new .resolve.old 
+
+                        #move old conf file to old conf file.bak
+                        mv "$EL" "$EL.bak"
+
+                        #move .newfile to resolve.conf file
+                        mv .resolve.conf "$EL"
+
+                        echo "Added $IP_LIST to $EL"
+                ;;
+
+                #case '-r'
+                        "$RE")
+
+                        #for each IP in IP_LIST
+                        for IP in $IP_LIST
+                        do
+                                #cat OLD into grep excluding IP lines,
+                                #storing results into NEW
+                                cat .resolve.old | grep -v "$IP" > .resolve.new
+
+                                #set OLD to NEW
+                                cat .resolve.new > .resolve.old
+
+                        done
+
+                        #move old conf file to old conf file.bak
+                        mv "$EL" "$EL.bak"
+
+                        #move .newfile to resolve.conf file
+                        mv .resolve.new "$EL"
+
+                        echo "Removed $IP_LIST from $EL"
+
+                ;;
+
+                #case else
+                        *)
+
+                        usage
+                ;;
+
+        
+        #end switch
+        esac
+
+#else
+else
+
+        usage
+
+#end
+fi