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I'm watching the error logs on my local setup. I'd like to have the errors print out in cowsay, you know, for fun. tail -f error_log | cowsay doesn't work. Any ideas?

icicleking
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cowsay can print what is presented to it on stdin, but gathers the lines together until stdin is closed (maybe it does so as well when some buffer overflows, but 15Mb of text was not enough to do so).

If you want cowsay to show every few lines you can pipe the output of the tail command into xargs and have it invoke cowsay on e.g every 3rd line:

tail -f error_log | xargs -n3 cowsay
Anthon
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  • didn't quite work. it spit out some of the error log in cowsay, then `This shouldn't happen at /System/Library/Perl/5.18/Text/Wrap.pm line 84.` – icicleking May 29 '15 at 13:41
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    @icicleking What system are you on? Maybe 'error_log' has overly long unwrappable lines. Have you tried with a small file `touch xyz ; tail -f xyz | xargs -n3 cowsay` and then in a different terminal window repeatedly doing `echo abc >> xyz`? – Anthon May 29 '15 at 14:05
  • As I can do this on my Linux Mint 17 system as `sudo tail -f /var/log/syslog | xargs -n3 cowsay` (sudo in order to read the `syslog` owned log file) – Anthon May 29 '15 at 14:07
  • From the path in your error message it looks like you are on OS X, maybe cowsay and/or xargs are different there. I have no way to test that. – Anthon May 29 '15 at 14:08
  • I am on OSX. It appears to work the same. I tested on a smaller file and I don't get the Wrap error. However, it doesn't "live update" the way tail -f usually does. Reading about xargs, it looks like it echos over the standard input. I wonder if that's too static to do the continuous monitoring. – icicleking May 30 '15 at 02:40
  • check that, it totally works on a small file. I was just writing the same thing to the file and didn't notice it changed. I'll update when I get it working on the error_log "cowsay parse error"! – icicleking May 30 '15 at 02:49