Writing try catch finally in shell

Question

Is there a linux bash command like the java try catch finally? Or does the linux shell always go on?

try {
   `executeCommandWhichCanFail`
   mv output
} catch {         


        

Answer 1

I found success in my script with this syntax:

# Try, catch, finally
(echo "try this") && (echo "and this") || echo "this is the catch statement!"

# this is the 'finally' statement
echo "finally this"

If either try statement throws an error or ends with exit 1, then the interpreter moves on to the catch statement and then the finally statement.

If both try statements succeed (and/or end with exit), the interpreter will skip the catch statement and then run the finally statement.

Example_1:

goodFunction1(){
  # this function works great
  echo "success1"
}

goodFunction2(){
  # this function works great
  echo "success2"
  exit
}

(goodFunction1) && (goodFunction2) || echo "Oops, that didn't work!"

echo "Now this happens!"

Output_1

success1
success2
Now this happens!

Example _2

functionThrowsErr(){
  # this function returns an error
  ech "halp meh"
}

goodFunction2(){
  # this function works great
  echo "success2"
  exit
}

(functionThrowsErr) && (goodFunction2) || echo "Oops, that didn't work!"

echo "Now this happens!"

Output_2

main.sh: line 3: ech: command not found
Oops, that didn't work!
Now this happens!

Example_3

functionThrowsErr(){
  # this function returns an error
  echo "halp meh"
  exit 1
}

goodFunction2(){
  # this function works great
  echo "success2"
}

(functionThrowsErr) && (goodFunction2) || echo "Oops, that didn't work!"

echo "Now this happens!"

Output_3

halp meh
Oops, that didn't work!
Now this happens!

Note that the order of the functions will affect output. If you need both statements to be tried and caught separately, use two try catch statements.

(functionThrowsErr) || echo "Oops, functionThrowsErr didn't work!"
(goodFunction2) || echo "Oops, good function is bad"

echo "Now this happens!"

Output

halp meh
Oops, functionThrowsErr didn't work!
success2
Now this happens!