Mac OS X log file viewer

Question

I'm looking for a robust log file reading application similar to LogFusion, but for the Mac OS.

The key features I'd like to use are:

• Row Highlighting
• Advanced, realtime Text Filtering
• Open logs files remotely (sftp)
• Limited loading. Only load what you're reading. This is important for large log files so the whole thing doesn't have to download. It's also helpful locally so it doesn't have to load the whole thing into memory to read it.
• Auto-Scroll (like "tail") to bring in the newest log lines.

The Console app built into OSX is okay, but there are some features I miss from my LogFusion days!

Thanks!

Answer 1

Take a look at lnav, the Logfile Navigator. It has most of the features you're interested in, as well as many others:

• Row Highlighting - You can set bookmarks on lines with the m hotkey. You can then move forward/backward through bookmarks using the u/U hotkeys. Bookmarked lines can also be copied to the clipboard using the c hotkey.
• Filtering - The :filter-in and :filter-out commands can be used to set filters so that only lines that match a given regular expression are shown or not-shown, respectively. Filtering is live, like most things in lnav.
• Large files/Limited Loading - lnav does not load the whole file into memory at any one time, but it does need to read through the whole file at startup to do indexing. So, in practice, loading extremely large files (multi-GB) does not work well.
• Auto-Scroll - When viewing the bottom of the file, the view is automatically scrolled to show the newest lines. When viewing other parts of the file, the view is locked to only display those lines, but new lines are still be indexed on the fly.

In addition to those features, lnav has many others:

• Multiple log files can be loaded at the same time and shown in a single view with messages being sorted by time.
• Log formats are automatically detected and new log formats can be defined using a JSON file with the appropriate regular expressions.
• Compressed (gzip and bz2) files are automatically decompressed.
• The timeline view shows a histogram of messages over time.
• The Pretty-print view will reformat any log message data (e.g. XML, JSON, or any structured data) so it is easier to read.
• Logs can be queried using SQL.
• Syntax highlighting

Here's a screenshot of lnav running in the OS X terminal:

Answer 2

Check out Log Transformer. It also has most of the features on your list including:

1. Row Highlighting. Write regular expressions (or just simple text matches) and define the color and format (bold/italic/underline) you prefer.
2. Advanced Real-time Text Filtering. Not only will it filter in real-time, it will filter as you are typing out your rule! It also features ordering of your rules, which is useful if you want a grep-like filter (only what matches) or the opposite "everything but this" type of filter.
3. Limited Loading - it uses a golang back-end to efficiently load only the lines that are streaming in (just like tail)
4. Auto-Scroll - If you scroll to the bottom of the log, it will auto-scroll to keep you viewing the latest line, but if you scroll up a bit you can easily move around the file even as lines stream into the bottom of the file (this works just like tail in the terminal).

It has other features including:

1. Remembers your log files so you don't have to keep opening them.
2. Remembers the last preset you applied to each of your log files so that you can make your perfect preset for each file.
3. Stores all of your presets in real time so you won't ever forget to save your work.
4. Play or pause log files on-demand. Especially useful for fast-moving files, or files that tend to get new lines at random times.
5. Watch multiple files at once, and easily switch between them in real time.
6. Has a terminal-like look and feel.

For tailing remote files, I recommend streaming a remote file to your local mac and then pointing Log Transformer to the local file, something like this: https://askubuntu.com/questions/917200/how-to-redirect-command-output-from-remote-machine-to-local-file-via-ssh