Checking Free Space:

In order to check the free and usage space per file system and directory and each sub directory we have two command

1. df
2. du

the ‘df’ command reports on a per file system basis. It report total disk space , disk space used , disk space free

#df –h

-h : used multipliers such as G or M for gigabytes and Megabytes

The ‘du’ command reports the number of kilobytes contained by the items within a directory

#du –s

#du –h

-s : used to request only the summary directory information

#du –s /etc

Aliases:

Aliases are shortcut names for large commands. If we have command that run often, but take a considerable amount of typing, we can reduce these to an aliases.

Alias c=clear

We can make a permanent entry of alias in .bashrc file

Type:

#vi .bashrc

alias c=`clear`

save and exit

Test your change by logging out, logging back and type the following

#alias

#c