How to define alias in Linux

1. view ~/.bashrc
It looks like below:

# .bashrc


# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi

# User specific aliases and functions
alias commandA='bash ./test.sh'


2.cd ~
  touch test.sh
  chmod 777 test.sh
  
3.run ~/.bashrc 
[e_dingl@test3tcapprh01 ~]$ . ~/.bashrc

4.in command line, type  "commandA" and enter

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Other Sample : 

# User specific aliases and functions
#Counts for incoming and processed
alias reads='echo -n "Incoming: "; find /home/pipe/Incoming/MultiDrive/MeterReads/ -type f | grep -v "Event" | wc -l; echo -n "Processed: "; find /home/pipe/Processed/MultiDrive/MeterReads/ -type f | grep -v "Event" | wc -l; date'