How do I run a shell script without using "sh" or "bash" commands?

These are the prerequisites of directly using the script name:

1. Add the shebang line (#!/bin/bash) at the very top.
2. Use chmod u+x scriptname to make the script executable (where scriptname is the name of your script).
3. Place the script under /usr/local/bin folder.
   • Note: I suggest placing it under /usr/local/bin because most likely that path will be already added to your PATH variable.
4. Run the script using just its name, scriptname.

If you don't have access to /usr/local/bin then do the following:

1. Create a folder in your home directory and call it bin.

2. Do ls -lA on your home directory, to identify the start-up script your shell is using. It should be either .profile or .bashrc.

3. Once you have identified the start up script, add the following line:

   PATH="$PATH:$HOME/bin"
   

4. Once added, source your start-up script or log out and log back in.

   To source, put . followed by a space and then your start-up script name, e.g. . .profile or . .bashrc

5. Run the script using just its name, scriptname.

Just make sure it is executable, using chmod +x. By default, the current directory is not on your PATH, so you will need to execute it as ./script.sh - or otherwise reference it by a qualified path. Alternatively, if you truly need just script.sh, you would need to add it to your PATH. (You may not have access to modify the system path, but you can almost certainly modify the PATH of your own current environment.) This also assumes that your script starts with something like #!/bin/sh.

You could also still use an alias, which is not really related to shell scripting but just the shell, and is simple as:

alias script.sh='sh script.sh'

Which would allow you to use just simply script.sh (literally - this won't work for any other *.sh file) instead of sh script.sh.

Add a "shebang" at the top of your file:

#!/bin/bash

And make your file executable (chmod +x script.sh).

Finally, modify your path to add the directory where your script is located:

export PATH=$PATH:/appropriate/directory

(typically, you want $HOME/bin for storing your own scripts)