These scripts and instructions are for developers on macOS running iTerm2. They allow splitting the view into multiple planes for different servers. Using an iTerm2 feature, a command only needs to be entered once and the command can be sent to all panes at once.

A use-case is when one needs to view Apache logs across say Prod 9 servers at once when debugging a Production bug or incident.

The start of each script can be customized easily for connecting to any list of host machines.

This guide is based on this tutorial: SSH to Multiple Hosts in Split Panes Using iTerm2.

Installation :wrench:

Install iTerm2

If you don’t have it installed, got to the iTerm2 homepage and download it from there.

I don’t know what support is like outside of macOS.

Set up script

We’re going to use a script in the AppleScript format here. But, don’t worry – I’ve done all the research and testing so now you only have to configure the first line and leave the rest as is.

Note that iTerm2 will only recognize files ending with .scpt. So .applescript will not work. But if you want syntax highlighting in your IDE, you can associate .scpt with .applescript.

Create a script.

$ touch ~/Library/Application\ Support/iTerm2/Scripts/my_script.scpt

Then add the content below as is:

  • my_script.scpt 
      set hostnames to { "foo.bar.com", "fizz.buzz.com"}

  if application "iTerm" is running then
    tell application "iTerm"
      create window with default profile
      tell current tab of current window
        select
        tell current session

          -- make the window fullscreen
          tell application "System Events" to key code 36 using command down
          split horizontally with default profile

          set num_hosts to count of hostnames
          repeat with n from 1 to num_hosts
            if n - 1 is (round (num_hosts / 2)) then
              -- move to lower split
              tell application "System Events" to keystroke "]" using command down
            else if n > 1 then
              -- split vertically
              tell application "System Events" to keystroke "d" using command down
            end if
            delay 1
            write text "ssh " & (item n of hostnames)
          end repeat
        end tell
      end tell
    end tell
  else
    activate application "iTerm"
  end if

Set hosts

Replace the hostnames with your own list and add as many as you want. The list can have valid hosts where you have SSH access to, including host aliases in /etc/hosts/ or ~/.ssh/config.

Restart

Close and reopen iTerm2 to get your script loaded.

Usage :runner:

Control multiple panes at once in iTerm2

  1. In iTerm2, open the Scripts menu and select your script.
  2. To enable sending of keyboard input to all panes, press CMD+Shift+I.
  3. Enter commands to run for all panes. e.g. ls or cd.
  4. Press the keys from step 2 to disable.

Example

How to tail Apache logs across servers :page_with_curl: :page_with_curl: :page_with_curl:

  1. Follow the steps above for a group of servers which have Apache running on them.
  2. Switch to a user with permissions to view Apache logs (owned by admin group). The ubuntu user was sufficient and let’s you avoid becoming root unnecessarily, but using that user no longer works so become root. 
     $ sudo su
  3. View the log files. 
     $ cd /var/log/apache2
 $ tail -f error.log