Shell Script Execution

4 basic fundamental things you should know about executing a shell script.

1. Locate the shell executable and give it as she-bang #!

Identify the full path of where the shell is installed.

$ which sh
/bin/sh

(or)

$ which ksh
$ which bash

Once you’ve identified the location of the shell executable, give that as shebang ( #! ) in the first line of shell-script file.
$ vim helloworld.sh #!/bin/sh echo "Hello World!"

2. Assign Execute Permission to the Shell Script file

If you don’t have execute permission on the script, you’ll get “Permission denied” error message as shown below.
$ ./helloworld.sh bash: ./helloworld.sh: Permission denied

If you want to give execute permission to group and others, do it as shown below.
$ chmod 755 helloworld.sh

3.Executing the script just like a regular Linux command

You can execute a shell script either by using the absolute path or the relative path.

sunitha@sunitha-laptop:~/bash_pgm$ ./hello.sh
hello world!