Shell script -- How to terminate parent if child fails to execute

Question

I have a shell script (parent) which is calling some other shell script. Suppose a child shell script fails to execute, then the parent shell script should also be stopped without executing the next child shell script. How can I automate this process?

Ex:

main.sh
//inside the main.sh following code is there
child1.sh //executed successfully
child2.sh //error occurred
child3.sh //Skip this process
//end of main.sh

Answer 1

The simplest mechanism is:

set -e

This means that the shell will exit whenever a child process exits with a fail status unless the status is tested as part of a conditional.

Example 1

set -e
false                        # Exits
echo Not executed            # Not executed

Example 2

set -e
if false                     # Does not exit
then echo False is true
else echo False is false     # This is executed
fi

Answer 2

child1.sh && child2.sh && child3.sh

In the above child2.sh is executed only if child1.sh completes successfully and child3.sh is executed only if child2.sh completes successfully.

Alternatively:

child1.sh || exit 1
child2.sh || exit 1
child3.sh || exit 1

In the above, the parent script exits after any of the children fail.