Terminology: terminal command to be invoked from any directory?

Question

Context: macOS Catalina zSh. The end goal is to be able to setup user scripts so that they can be invoked via CLI at an arbitrary data location.

Question: What is the word (Terminology) for: the terminal command to be invoked from any directory? The correct word / phrase would allow me to Google the subject matter and inch forward to the goal defined below.

Example: the command ls can be issued from any directory and return output. Likewise when lsusb was installed with homebrew: lsusb will work from any directory: somehow when lsusb was installed, the system was configured such that it knows where to look to find lsusb.

Path Variable: I understand that the $PATH variable contains path information:

babygrand:~ user$ echo $PATH

returns

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

I suspect that /etc/paths is configures $PATH at startup:

babygrand:~ user$ cat /etc/paths

/usr/local/bin /usr/bin /bin /usr/sbin /sbin

The output paths seem to be a variation of the File System Hierarchy, which poses a similar question to my goal, but not my Terminology question

GOAL: I would like to Google the word / term of the subject matter and learn best practice how to enable a script to be run from any directory. I am faced with a decision as to whether to add another path or to choose an one of the above existing paths that has been already configured into the $PATH variable.

The ability to invoke my script at an arbitrary directory is of significant utility: the script performs work on pdf files, which could be located anywhere in the file system. My script calls an executable to stamp pdf documents.

Clarification: The subject matter is not that of the "subfolder" problem posed at: https://apple.stackexchange.com/q/366127/187540 This is excellent reading as it is somewhat related to directory management.

Answer 1

As far as I know, there is no specific well-known term for what you seem to be asking, other than just saying that the application/utility/script is or should be placed in PATH, as a shorthand for "in a directory included in executable search path". Unfortunately the short form is not very googleable and the long form is rarely used.

If you intend your script to be available for all users, the "standard" way would be to add (or link) it to /usr/local/bin, which would be the expected location for scripts and tools managed for the local system administrator and intended to be usable for all users of the system. This directory is normally included in the system default $PATH for users.

Note that in your example, /usr/local/bin is listed in $PATH before the /usr/bin and /bin directories of the system standard tools. This allows the system administrator to override the standard tools by placing e.g. a newer version of some tool to /usr/local/bin using the exact same name as the corresponding standard system tool.

If the script was intended for all system administrators only, then respectively /usr/local/sbin would be the expected location. However this is not always automatically added to the default $PATH for system administrators.

But if you want to set it up for yourself only, the easiest way would be to set up a directory for your scripts (e.g. $HOME/bin, although you could name it anything you wish), and add it to the system default $PATH in your personal login script.

If you modify the default $PATH, you can either completely replace the existing value (not recommended unless you know what you're doing), or alternatively prepend or append your custom script directory to $PATH.

Appending $HOME/bin to the current $PATH:

export PATH="$PATH:$HOME/bin"

By appending your custom directory, the scripts within it will be placed last in the search order, guaranteeing that you won't accidentally cause problems to yourself by naming your script the same as some standard system tool.

Conversely, if you want the ability to override the standard tools with your own, you can prepend your script/tool directory to $PATH:

export PATH="$HOME/bin:$PATH"

To make this change permanent so it affects al shell sessions and survives rebooting, just add the line above to your ~/.profile file (you can create it if it doesn't exist already).