how do I refresh my wired ethernet connection from command line?

What is the command line equivalent of unchecking "Enable Networking" (disabling networking) and then re-enabling?

In my environment, there are multiple networks which require me to physically move my network cable. Sometimes my connection does not refresh properly, so I disable/re-enable networking to refresh my connection. Being able to do this from the command line would be much more efficient for me.

I'm using 12.04 LTS.

Solution 1:

I'd use the nmcli commands for that purpose:

nmcli nm enable false && nmcli nm enable true

man page:

DESCRIPTION
       nmcli is a command‐line tool for controlling NetworkManager and report‐
       ing on its status.  It is not meant as a full replacement for nm‐applet
       or other similar clients but as a complementary utility to those pro‐
       grams.  The main usage for nmcli is on servers, headless machines or
       for power users who prefer the command line.

       [...]

  nm     NetworkManager
          Use this object to inquire and change state of NetworkManager.

         [...]

          enable [true|false]
                 Get networking‐enabled status or enable/disable network‐
                 ing by NetworkManager.  All interfaces managed by Net‐
                 workManager are deactivated when networking has been dis‐
                 abled.
                 Reference to D‐Bus:
                 interface: org.freedesktop.NetworkManager
                 method:    Enable
                 arguments: TRUE or FALSE

Solution 2:

Please try:

sudo service network-manager restart

Solution 3:

You can try:

nmcli connection reload

It will reload all connection files from disk.