Handy for debugging and watching what's going on while it's going on. Use tail with the “f” option, which lets you read the end of a growing file. Examples:
$ tail -f /var/log/messages$ tail -f /var/log/syslog $ tail -f /var/log/mail.log $ tail -f /usr/local/httpd/logs/error_log
Need to capture some output to a terminal that can't be redirected easily to a file with “>”? Use script. At a command prompt type script, then do what ever you need to log and exit. The log of _ALL_ the stuff sent to your terminal finds its way into a file called typescript! Example:
tux@coollinuxbox:/home/tux$ scriptscript: WARNING: script session is not secure against eavesdropping/hijacking! script: read /usr/doc/bsdutils/README.script for details. Script started, output file is typescript tux@coollinuxbox:/home/tux$ python python commands control-D tux@coollinuxbox:/home/tux$ exit Script done, output file is typescript tux@coollinuxbox:/home/tux$ cat typescript Script started on Thu Oct 12 12:03:22 2000 tux@coollinuxbox:/home/tux$ python Python 1.5.2 (#1, Dec 15 1999, 11:15:06) [GCC 188.8.131.52] on linux2 Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam >>> 45+89+12.25+63.21 209.46 >>> 70/12 5 >>> 70%12 10 >>> tux@coollinuxbox:/home/tux$ exit Script done on Thu Oct 12 12:04:43 2000 tux@coollinuxbox:/home/tux$
Wanna make a clone of one hardisk to another? Use tar. Hook up your soon-to-be-cloned hardisk to your system (power off during this operation). Boot your box. As root, cd to /. Mount the new hard drive on /mnt. Then run the following command:
$ tar clf - . | ( umask 0; cd /mnt; tar xvf - )
c = createl = stay on local filesystem (don't cross filesystem boundaries)f = file (the next argument is the name of the tarfile or “-”)- = write to standard out or read from standard inx = extractv = verbose
“umask 0” ensures that the new files have the same permissions as the old ones.
Practical Task Scheduling Deployment
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.View Now!
|The Firebird Project's Firebird Relational Database||Jul 29, 2016|
|Stunnel Security for Oracle||Jul 28, 2016|
|SUSE LLC's SUSE Manager||Jul 21, 2016|
|My +1 Sword of Productivity||Jul 20, 2016|
|Non-Linux FOSS: Caffeine!||Jul 19, 2016|
|Murat Yener and Onur Dundar's Expert Android Studio (Wrox)||Jul 18, 2016|
- Stunnel Security for Oracle
- The Firebird Project's Firebird Relational Database
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- SUSE LLC's SUSE Manager
- Managing Linux Using Puppet
- Non-Linux FOSS: Caffeine!
- My +1 Sword of Productivity
- SuperTuxKart 0.9.2 Released
- Doing for User Space What We Did for Kernel Space
- Google's SwiftShader Released
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide