TERMINAL HELP MAC

TERMINALS HELPS

Clear DNS Cache in OS X Yosemite 10.10.4 & OS X 10.10.5

From OS X 10.10.4 moving onward to 10.10.5, including 10.11, Apple has ditched discoveryd and has replaced it (or rather, reverted back to) mDNSResponder. Thus, to clear DNS caches in OS X Yosemite 10.10.4, and 10.11 El Capitan, and presumably onward, the command string is as follows:

sudo dscacheutil -flushcache;sudo killall -HUP mDNSResponder;say cache flushed
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Step 1: Launch Terminal, found in /Applications/Utilities/ or launched through Spotlight

Step 2: Type the following command at the prompt to backup hosts file to documents folder:

    sudo cp /private/etc/hosts ~/Documents/hosts-backup



Step 3: Type the following command at the prompt to open hosts file:

     sudo nano /private/etc/hosts



Step 4: Enter the administrator password when requested, you will not see it typed on screen as usual with the command line

Step 5: Once the hosts file is loaded within nano, use the arrow keys to navigate to the bottom of the hosts file to make your modifications

Step 6: When finished, hit Control+O followed by ENTER/RETURN to save changes to /private/etc/hosts, then hit Control+X to exit out of nano

Step 7: Verify your hosts modifications. You may need to clear DNS cache first.



If you want to restore the modified hosts to the backup of the original file use this command:

    sudo cp ~/Documents/hosts-backup /private/etc/hosts