groups. Although rarely—if ever—used on a local or standalone workstation,
quotas are definitely a way of life at the enterprise level of computing. Usage
limits on disk space not only conserve resources but also provide a measure of
operational safety by limiting the amount of disk space any user can consume.
Disk quotas are more fully covered in Chapter 13, “Managing Users.”
Checking Log Files
Many of the services and programs that run on your computer save data in log
files. Typical data include success and error messages for processes that are
attempted and lists of actions. Some of these log files are extremely technical,
while others are easily read and parsed by regular users who you know what
they are looking for. Most log files can be found in /var/log/ or its
subdirectories.
Typically, log files are used to learn about something that happened recently,
so most admins are interested in the most recent entries. In this case, using
tail is commonly used to read just the most recent 10 lines:
Click here to view code image
matthew@seymour:~$ tail /var/log/boot.log
- Starting
[ OK ]
Starting save kernel messages
[ OK ] Starting
[ OK ]
Starting [ OK ]
Starting deferred execution scheduler
[ OK ]
Starting regular background program processing daemon
[ OK ] Stopping
save kernel messages [ OK ]
Stopping
anac(h)ronistic cron [ OK ]
Starting CUPS
printing spooler/server [ OK ] *
Starting CPU interrupts
balancing daemon [ OK ]
There isn’t anything terribly interesting in this quote of today’s boot.log
on this machine, but it is sufficient to show how reading the last few lines of a
log file works.
You are more likely to want to be able to find out whether something specific
is mentioned in a log. The following example shows how to use cat and