Equivalence of "if then" statements in bash


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# 1  
Equivalence of "if then" statements in bash

Would these two sections of code be equivalent?
The original is the first one, followed by the new
implementation.


Code:
  if ["$num1" -lt "$pmin"]; Then 
     ... 
  else   
    if ["$num2" -lt "$pmin"]; Then 
       ... 
    fi  
  fi

Code:
  if ["$num1" -lt "$pmin"]; Then 
     ... 
  else if ["$num2" -lt "$pmin"]; Then 
       ... 
  fi



# 2  
How would they ?
# 3  
Instead of else if, use elif, then it should work, provided you use a lowercase T in then and you use spaces around the square brackets...

Last edited by Scrutinizer; 07-05-2015 at 12:39 PM..
This User Gave Thanks to Scrutinizer For This Post:
# 4  
Quote:
Originally Posted by kristinu
Would these two sections of code be equivalent?
The original is the first one, followed by the new
implementation.


Code:
  if ["$num1" -lt "$pmin"]; Then
     ...
  else
    if ["$num2" -lt "$pmin"]; Then
       ...
    fi
  fi

Code:
  if ["$num1" -lt "$pmin"]; Then
     ...
  else if ["$num2" -lt "$pmin"]; Then
       ...
  fi



The second example is missing an fi; you have 2 ifs, but only one fi. Better is, as Scrutinizer pointed out, to use elif ...; then.

In bash, you can use:
Code:
if (( num < pmin )); then

Code:
if (( num1 < pmin )); then

# 5  
An 'else if' and an 'elif' are two different things.

Here are some basic if/else examples
Code:
if true
then	echo true
fi

true && echo true

if ! false
then	echo true
else	echo false
fi

! false && echo true || echo false
! false && \
	echo true || \
	echo false

if true
then	if false
	then	echo true-false
	else	echo true-true
	fi
fi

if true
then	if false
	then	echo true-false
	else	echo true-true
	fi
else	echo false
fi

if true
then	echo true
elif false
then	echo false
else	echo something else?
fi

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