Bash Basics: Sorta try/catch/finally block

try_catch.sh

#!/bin/bash

# Shows the right and wrong ways of try/catch/finally blocks in shell scripting.
#
# OUTPUT:
#
# *Try* 1 (FAIL) ---------
# aaa
# bbb
# ./try_catch.sh: line 34: thisisabadcommand: command not found
# You shouldn't see this
# *Finally*
# 
# *Try* 2 (FAIL) ---------
# aaa
# ./try_catch.sh: line 46: doesntcatchthisbadcommand: command not found
# You shouldn't see this before the catch
# ./try_catch.sh: line 48: thisisabadcommand: command not found
# *Catch*
# *Finally*
# 
# *Try* 3 (SUCCESS) ---------
# aaa
# ./try_catch.sh: line 59: catchesthisbadcommand: command not found
# *Catch*
# *Finally*
# 

# FAIL - this will not work as a TRY/CATCH
echo "*Try* 1 (FAIL) ---------"
{
  echo aaa
  echo bbb
  thisisabadcommand
  echo "You shouldn't see this" 
} || {
  echo *Catch*
}
echo *Finally*
echo

# FAIL - this enters "catch" but only because the final command is a problem
echo "*Try* 2 (FAIL) ---------"
{
  echo aaa
  doesntcatchthisbadcommand
  echo "You shouldn't see this before the catch" 
  thisisabadcommand
} || {
  echo *Catch*
}
echo *Finally*
echo

# SUCCESS - last echo in top block is never reached. Glue commands together with &&
echo "*Try* 3 (SUCCESS) ---------" &&
{
  echo aaa &&
  catchesthisbadcommand &&
  echo "You shouldn't see this (and you won't)"
} || {
  echo *Catch*
}
echo *Finally*