====== Using Aliases in CentOS ======
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Aliases are a way of assinging a complex command to an easy to remember word. Looking at the command below:
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        ip addr |grep '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'
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This returns just the IP part of the output from an //**ip addr**// command, making the output much easier to read, however remembering and typing the command requires more effort than it saves. For this then we can create an alias.
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I want an alias called **showip** that acutally does the same as typing ip addr |grep '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'
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You need to edit the .bash file for the logged in user who will use this alias. I am logged in as pi, so I will edit that bash file.\ 
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Navigate to root:
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     cd /root
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Show the list of files:
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     ls -al to show file list, you will see a list of files, including one called .bashrc\\ 
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Edit the .bashrc file by entering:
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      vi /root/.bashrc
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My default .bashrc file looks like this:
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        # .bashrc
        
        # User specific aliases and functions
        
        alias rm='rm -i'
        alias cp='cp -i'
        alias mv='mv -i'
        
        # Source global definitions
        if [ -f /etc/bashrc ]; then
                . /etc/bashrc
        fi
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Now add the new alias:
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        alias showip=" ip addr |grep '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'"
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save the file and exit:
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        :wq
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You have to restart the bash for any new aliases to work
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        . .bashrc
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If you want to see if the alias is now listed, from the command prompt just type:
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        alias
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You should now be able to type your new command at the command line and get an output:
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        showip
            inet 127.0.0.1/8 scope host lo
            inet 192.168.27.30/24 brd 192.168.27.255 scope global eth0
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