As we get different routes in the journey of life , we get different paths in the flow of our code , which to select depends on our logic , it may be right or wrong , but it depends on our conditions !!

if condition

if this is true then i would do that

Syntax 0:

 if condition
       then
       ...
       ...
    else
         ...

fi 

Syntax 1:
           if condition
                then
                ....
                elif another_condition
                    then
                          ....
                else
                         ....
            fi 
        

test command or [ expr ]

Am i a hero ?

If test returns zero then I am a hero , or else any non-zero value from the test clearly says I am not a hero.

Syntax:

Can be used on : Integer ,File types and Character strings .

Conditions :

For strings we can use == and != , for equals and not equal to conditions.

For file we can use -[ s,f,d,w,r,x,] file , can be used to check ,non empty ,file,directory, wrx permissions respectivly.

Local operations like !,-a,-o i.e NOT,AND,OR can be used with expressions .

Case statement

Case in expression then go to the referred case number or the pattern

Syntax:

case expression in
pattern1) execute commands ;;
pattern2) execute commands ;;
...
esac