How execution flows during runtime within shell script.

Any script executed in any shell has only 1 way of execution i.e sequential which means the execution flow is top to bottom hence the commands written in top will be executed first than written in below.

Also, to debug script execution i.e. to check what went wrong sh -x should be used.

An executable permission (chmod +x [removed]) should be given to script file as this is essential to make file available for execution.