Shell tool examples in the terminal

eg Explains

Article from Issue 258/2022

Need to know how to use a command-line tool? eg provides real life examples, and it is easier to access than the man pages.

On forums and in discussion groups, you increasingly find people claiming that using the command line is an anachronism. They say that it should be possible to handle any task with graphical tools. This kind of statement shows that whoever posted the comments has never seriously tried to work with a terminal. Anyone who is aware of the speed and elegance of working at the command line would never agree that graphical tools alone would be preferable. I admit to using a hybrid of command line and graphical tools on the Plasma desktop. I have increasingly used both, equally, in combination for many years, and there is no way I would want to do without the command line given this very satisfying division of labor.

Complex Man Pages

There are several ways to approach working in a terminal as a newcomer with the willingness to learn. The first place to start for many users is the man pages, which are great as a reference because they list all the options, flags, and parameters for a tool. But if you actually want to learn how to use command-line interface (CLI) tools, the man pages offer very limited help – in fact, they are more likely to scare off most newcomers. Hands-on examples provide far more easily digestible information, and there are countless examples on the web. The trick is finding the right example from such a massive selection.

This is where the interactive tool eg enters the scene. It stands for exempli gratia (e.g. for short), which comes from Latin. The name makes sense, until you need to search the web or your hard drive for "eg" and are bombarded with matches. eg's self-description states that it provides examples of common uses of command line tools. I checked how well this works.

Quickly Installed

To do so, I first visited the tool's GitHub page [1] to see what the install looks like. The tool is not available from the package archives of most of the popular Linux distributions. You can install it with pip, the package installer for Python packages from the Python Package Index. But to do this, you may first need to install the python3-pip package on your machine from the package manager, if it is not already in place. You then retrieve eg with the pip install eg command and store it on your hard disc.

Once eg is installed and ready to use, there is no need for configuration, but it is possible. As your first official step, type the eg --list command, which shows you an alphabetically sorted list of the 80 or so tools and commands currently supported (Figure 1). If the system outputs a command not found message when you do this, you will probably have to log off the desktop and log back on again. The system will then include the installation directory in its path.

Figure 1: Installing eg is painless. If you have not already done so, you need to install the python3-pip package first.

Examples of one of the listed commands are easy to access by calling eg NAME. You will notice that some entries have only a few lines (Figure 2), while others – such as the entry for Git – have several hundred lines. Once you have finished reading an entry, pressing Q will return you to the prompt. If you do not want to continue using eg after a test, simply remove it by typing pip uninstall eg.

Figure 2: Working with eg is very simple. You can see the output for the cd (change directory) command here.

Scope for Your Own Ideas

eg stores in $HOME/.local/lib/python3.9/site-packages. Check out the "Installation Path" box for more details. In the installation directory, you will find the supported commands and tools below the eg/examples/ folder in Markdown format. If you want to add examples or parameters yourself, open the corresponding Markdown file and make your changes.

Installation Path

You install eg in $HOME/.local/lib/, and the executable is located in $HOME/.local/bin. You need to make sure that this directory is in your path variable. You can determine whether this is the case by typing echo $PATH. If the directory is missing from the list, you can add it temporarily by typing export PATH="$HOME/.local/bin:$PATH". But this configuration will not survive the next reboot. Use the entry shown in Listing 1 to store it permanently in your $HOME/.profile. Most desktop environments preconfigure the shell appropriately. But the if query in Listing 1 only integrates the path if the directory already exists at login time. You may need to log out and back on again after installing eg.

Listing 1


# set PATH so it includes user's
# private bin if it exists
if [ -d "$HOME/.local/bin" ]; then

Also, eg lets you store your own entries in the data structure. To do this, create a file named in examples/, and eg will load it automatically from there. Ultimately, the tool does nothing more than match a command you type, such as eg git, with the files in the default and custom directories (including subfolders). If eg finds a matching entry, it outputs the entry, piping it through the less pager (Figure 3) to do so.

Figure 3: In the installation directory below examples/, you will find the Markdown files that act as the basis for the output. You can customize these files or create your own examples.

If you want to organize your own creations in a separate directory, create a configuration file named $HOME/.config/eg/egrc or $HOME/.egrc. In the simplest case, this will look something like Listing 2. You can also define an alternate location for the default examples/ directory. The output can also be extensively customized to suit your own needs, for example, by adding colors. Examples of this can be found on the project's GitHub page [1].

Listing 2


custom-dir = $HOME/my-eg

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