Function - Make your function return an exit status

Shell Programming and Scripting
1

Hi All,

Good Day, seeking for your assistance on how to not perform my 2nd, 3rd,4th etc.. function if my 1st function is in else condition.

#Body

function1() 
{
if [ - e test.xt] 
then
echo "exist" 
else
echo "not exist" 
} 

#if not exist in function1 my all other function will not proceed. 

function2() 
{
cat test.txt
} 

#Main
function1
function2
etc..

if i put my function1 and function2 in main it always proceed on function 2 even though theres an error in function1. im not sure how to start.

TIA

2
  1. Make your function return an exit status.
  2. Act on the exit status.
if [ - e test.xt ] 
then
  echo "exist"
  return 0
else
  echo "not exist"
  return 1
fi

For practical reason in the shell the exit status 0 means ok/true.

if function1
then
  function2
fi

function1 &&
  function2

The logical AND needs to evaluate(run) the RHS only if the LHS was true.

1 Like
3

oww.. i can also put the function inside if?

--- Post updated at 12:39 PM ---

where should i put the condition of function? in last?

4

Yes, a function behaves like a command.

if command1; then command2; fi

If command1 was successful (exit 0) then run command2.
The same can be achieved with the logical AND:

command1 && command2
5

For that matter, there's already return values here you aren't checking.

function2() 
{
        cat test.txt # If this fails, $? will be nonzero
} 

if ! function2
then
        echo "Could not execute function2" >&2
        exit 1
fi

Just be careful not to alter the value of $? by doing anything else, or set it to what you want with the 'return' statement.

1 Like