Installing and Using Command Line Tools

There are many command line tools and scripts you can download and install that are very useful for Mac Admins.

(Just a representative list, certainly not complete.)

Some of these tools provide installer packages that deploy the tool in the proper directory – usually /usr/local/bin so that you and other users can use it. (/usr/local/bin is in the macOS default PATH.)

However, many of these tools, such as munkipkg or my own quickpkg just come as a git project folder, with no or few instructions to get it set up. The assumption is, that when you use these tools you are familiar enough with the shell to make them work.

There are actually several approaches to getting these tools to actually work for you, most with different upsides and downsides. This post will talk about a few of them.

Getting the Tool

Before you can choose a method to run the tool, you need to get it. Many admins share their scripts and tools through a hosted service like Github. My quickpkg tool, for example, is a python script hosted as an open Github repository.When you follow that link you will see the main project page. The page has a menu area up top, a file list in the middle and below an area where an introduction to the project (the ReadMe file) is shown. It is worth to read the ReadMe in case they have special installation instructions.

Download the Release

Git is a version management tool that lets you track changes throughout the coding process. Github is one popular service to host these projects online. Contributors of a project have the option of marking steps of the project as a ‘release.’ Releases are considered a tested and stable stop in between less reliable developmental steps.

Releases will be shown in the project’s ‘releases’ page (link in the middle of the page, above the file list). (quickpkg releases page

On the releases page you will see a list of releases with the newest on top. At the very least each release will have a snapshot of the project’s code as a zip or tar.gz archive. Some projects provide other archives or installers such as dmg or pkg as well.

Download the Current Project

Some projects do not manage releases. (You will see ‘0 releases’ in the tool bar.) Then you can still download the most recent version of the project. There is a large green ‘Clone or download’ button on the right area above the project’s file list for this. When you click that button it will expand to show some more options.

‘Download ZIP’ will simply download an archive of the current state of project, much like the release download would.

When you download the archives, either through the releases page or from the ‘Download ZIP’ button, the resulting project folder will not be connected with the Github project any more. If you just want to use the current version, then that is fine and will serve you well. If you want an updated version in the future you will simply download the newer version and replace the tool you already have.

If you rather use git to download and manage the code, then you can do that here, too. However, that is a topic for another post.

Using the Tool

However you get the project you will now have a directory with the tool and any supporting files. You can already change directory to this folder in Terminal (drag the folder on to the Terminal icon to open a new Terminal already changed to it) and run the tool directly:

$ cd ~/Projects/quickpkg/
$ ./quickpkg
usage: quickpkg [-h] [--scripts SCRIPTS] [--preinstall PREINSTALL]
                [--postinstall POSTINSTALL]
                [--ownership {recommended,preserve,preserve-other}]
                [--output OUTPUT] [--clean] [--no-clean] [--relocatable]
                [--no-relocatable] [--sign SIGN] [--keychain KEYCHAIN]
                [--cert CERT] [-v] [--version]
                item_path
quickpkg: error: too few arguments
This will do for tools that you use rarely. But for tools that you want to use frequently typing the path to the tool is quite cumbersome.

Put it in the PATH

The PATH environment variable lists the directories where the shell looks for commands. You could add the project directory of the tool you just added to the PATH, but that would be tedious to manage.

An easier solution is to copy the tool to /usr/local/bin. This is the designated directory for custom commands. /usr/local/bin is also in the default macOS PATH.

However, copying the tool has some downsides. When the tool get’s updated you will have to copy the newer version, as well. Also some tools may require additional resources or libraries that reside in its project directory.

Instead of moving the tool, you can create a symbolic link to the tool in /usr/local/bin.

I keep the project folders of tools in ~/Projects so I use the command:

$ sudo ln -s ~/Projects/quickpkg/quickpkg /usr/local/bin
$ ls -al /usr/local/bin/quickpkg 
lrwxr-xr-x  1 root  wheel /usr/local/bin/quickpkg -> /Users/armin/Projects/quickpkg/quickpkg
Since symbolic links use paths, this has the advantage that when you download a newer version of the project to the same location, the link will point to the new version.

Putting links to a tool in /usr/local/bin has a few downsides (or upsides, depending on your perspective):

  • you need to have administrator privileges to change /usr/local/binlinks/tools you add to /usr/local/bin affect all users on that Mac

Set your own PATH

When you want to have the tools only affect your shell environment you need to do a bit more work.

First you need to choose a location where you tools or links should live. I have created a directory ~/bin for that purpose.

$ mkdir ~/bin
When you don’t want anyone else on the Mac to see what you are doing in that directory, you can remove everyone else’s access to it:
$ chmod 700 ~/bin
If you want you can also hide the directory in the Finder:
$ chflags hidden ~/bin
(Use the same command with nohidden to make Finder show it again.)

(To test the following properly, you need to delete the symbolic link we created earlier in /usr/local/bin. If that still exists the shell will use that, since it comes earlier in the PATH.)

You can create a symbolic link to the in ~/bin with

$ ln -s ~/Projects/quickpkg/quickpkg ~/bin
However, these still will not work, since we need to add the ~/bin directory to your personal PATH.

To do that you need to add this line to your ~/.bash_profile or ~/.bashrc:

export PATH=$PATH:~/bin
(Read more about how to create a bash profile here and here. This assumes you are using bash, the default on macOS. Other shells will have other locations where you can change environment variables.)

Then open a new Terminal window or type source ~/.bash_profile so that the new profile is loaded in the current window and try running the command.

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