MacOS – Tail multiple log files

logsmacostailterminal

I have an application which generates new log files each time it is run. They all go to one folder, with filenames like this, and the next log isn't started until the current one is finished.

Log-20140122102407.txt
Log-20140122102739.txt
Log-20140122103640.txt
Log-20140122162121.txt
Log-20140122163145.txt

I want to monitor the current progress in a terminal window like tail -f but that won't work with multiple files. I've heard of multitail, but don't know how to use it, and I don't want my terminal window split into multiple sections.

Best Answer

tail

tail can tail multiple files. Donovan Bray's article explains more, tail: can tail multiple files simultaneously, who knew? and other tail tricks.

To tail multiple files, pass in a file pattern:

tail -f Log-*

multitail

You can ask multitail to combine the output of multiple files. The examples page contains a useful approaches and tricks.

This command combines and tails two logs:

multitail /var/log/apache/access.log -I /var/log/apache/error.log

If you need to tail any logs in a folder, including those actively being created, use the -q flag:

multitail -q 'test*'

This will tail any files matching the pattern test*, including those that appear after the command has been issued. Thanks to @folkert-van-heusden for this suggestion and code fix.

If you have homebrew installed, you can install multitail using the Terminal.app command:

brew install multitail

Related Solutions

How to write a script to open multiple terminal tabs and execute code in them

This is a little bit hacky, but you can achieve this in AppleScript. If there is a predetermined number of tabs you want, and preset commands you wish to run, this isn't difficult.

tell application "Terminal"
    -- Activate it.
    activate

    set targetWindow to 0

    -- Get a window that's not busy.
    -- If there are no open windows, open one.
    if count of windows is greater than 0 then
        repeat with currentWindow in windows
            if currentWindow is not busy then
                set targetWindow to currentWindow
            end if
        end repeat
    else
        do script ""
        set targetWindow to window 1
    end if

    -- Do command 1.
    set firstCommand to "cd ~/Desktop; clear"
    do script firstCommand in targetWindow

    -- Open a new tab.
    tell application "System Events" to tell process "Terminal" to keystroke "t" using command down

    if count of windows is greater than 0 then
        repeat with currentWindow in windows
            if currentWindow is not busy then
                set targetWindow to currentWindow
            end if
        end repeat
    else
        do script ""
        set targetWindow to window 1
    end if

    -- Do command 2.
    set secondCommand to "cd /Applications; clear"
    do script secondCommand in targetWindow

    -- And so on...
end tell

Of course, replace firstCommand with whichever command you actually want to run, and so on. For whatever reason, Terminal doesn't really have an accessible way to create new tabs through AppleScript, so the long, hacky looking line in the middle just tells Terminal to type ⌘T to open that new tab, and then new commands will execute in it.

You can run this AppleScript as is, or use it in Automator to create a new service, which you can then execute from anywhere using a keyboard shortcut if you'd like.

Extras - If you want to fire some script/command in the newly opened terminal session, you can refer this

MacOS – n OS X ‘tail’ tool that can monitor remote log files

You may try to use a combination of multitail and ssh.