echo (Echo input)
The echo command is used for displaying a line of text/string that is included in the argument.
echo with string
When an argument is a string, the echo command returns the string itself.
Command Line - INPUT
echo ABC
Command Line - RESPONSE
ABC
echo with variable
When an argument is a variable, use $ before the variable. the echo command returns an assigned string to the variable.
Command Line - INPUT
ABC=56
echo $ABC
Command Line - RESPONSE
56
echo with string and variable
You can connect strings and variables in the echo command.
Command Line - INPUT
ABC=56
echo ABC$ABC
Command Line - RESPONSE
ABC56
" " double quotation and ' ' single quotation
You can connect strings or variables with special characters or spaces with the " " or ' ' quotation; however, there is a slight difference.
" " double quotation
with the " " quotation, variables are converted to assigned strings.
Command Line - INPUT
ABC=56
echo "ABC$ABC ABC"
Command Line - RESPONSE
ABC56 ABC
‘ ’ single quotation
with the ' ' quotation, variables are not converted to assigned strings. $ is considered as a part of the strings.
Command Line - INPUT
ABC=56
echo 'ABC$ABC ABC'
Command Line - RESPONSE
ABC$ABC ABC
You can also learn this topic offline. Click 
.
More Topics to Explore
User Models
Chapter 6. Remote Collaboration
Web Server Setup – Nginx
Install Python
