Create a file like more, adb

Question

In Ubuntu if I type which more, it will display the path of the more command as /bin/more, indicating it is a file. But I don't see any extension for it nor a type associated, probably because they are simple executables. How can I create such a file which could echo a simple string?
I don't want to create a .sh file because if I want to pass the file as a command with another command, I'd have to type .sh as well.
TIA

Answer 1

Un*x like OS are not interested in file extensions. To make a shell script executable, put

#!/bin/sh

as first line in the script to define the interpreter (or #!/bin/bash if you need bash extensions, or whatever shell you chose). And change the mode to executable:

chmod a+x <filename>

You have to provide the full or relative path to the executable, if it is not in a directory in your PATH environment.

Edit:

If there is a ./bin subdirectory in your home directory, this will usually be included in your $PATH when logging in (see the .profile script). So you may create $HOME/bin and put the executable file there

Answer 2

You do not need to use the .sh extension for your shell scripts. They should start with a shebang to signal that it's a shell script. #!/bin/bash is the shebang for a bash script, or if you'd like the OS to decide which shell to use, based on the default shell use #!/bin/sh.

To be able to execute the script as a command, just by typing the name, it should have; a shebang, executable permissions, and should be located in a directory which is included in your PATH environment variable.

You can see all of these locations by using:

echo $PATH

The output should be:

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

Once those three conditions have been met, your script will execute by just typing the name.