#!/bin/bash

# Variables
SUB_SCRIPTS=" \
  a.sh \
  b.sh \
"

# Functions
function cmdExists() {
  if [ ! -e $1 ]; then
     return 1;
  else
     return 0;
  fi
}

function hasPermToExec() {
  if [ ! -x $1 ]; then
    return 1;
  else
    return 0;
  fi
}

function executeScript() {
  sh $1;
  return $?;
}

# first parameter is the error description
function reportErrorAndExit() {
  echo "Error: $1";
  exit 1;
}

# Execution starts here
for i in $(echo $SUB_SCRIPTS | xargs); do

 # Check if command exists 
 cmdExists $i
 if [ "$?" -ne 0 ]; then
   reportErrorAndExit "Script $i not found";
 fi

 # Check if the user has permission to execute script
 hasPermToExec $i
 if [ "$?" -ne 0 ]; then
   reportErrorAndExit "No permissions to execute script $i";
 fi

 # Execute Script and check return value
 executeScript $i
 if [ "$?" -ne 0 ]; then
    reportErrorAndExit "Script $i exited with an error";
 fi

done;