In this chapter, we will start off with a short introduction to Vim and look at the most basic commands to help you get started with basic CRUD (create, read, update, delete) operations. We will then upgrade the shell interpreter to zsh and also give it superpowers with the awesome oh-my-zsh framework. We will look at some basic regular expressions such as searching some text using grep. Then, we will unleash the power of Unix pipes and run embedded commands using subshells. The later part of the chapter will help us understand how we can boost productivity and automate a lot of our day-to-day work by showing some of the more advanced shell scripting techniques.
In this chapter, we will cover the following:
- Working with Vim
- Managing zsh using the
oh-my-zshframework - Writing and running super powerful one line commands using pipes and subshells
- Exploring the shell scripting libraries
We will focus on editing files. For that we need to choose a file editor. There are a bunch of options but considering that the fastest way to edit files is, of course, without leaving the terminal. We recommend Vim. Vim is an awesome editor! It has a lot of configuration options with a huge community that has produced lots of plugins and beautiful themes. It also features advanced text editing, which makes it ultra-configurable and super-fast.
So, let's proceed. Open the terminator and type sudo apt install vim to install Vim:
Vim is renowned for its exotic keyboard controls and a lot of people avoid using Vim because of it. But once you get the basics, it's super easy to use.
Let's start vim with no arguments:
This is the default screen; you can see the version on the second line.
- To start editing text, press the Insert key; this will take us to the insert mode, where we can start typing. We can see we are in the insert mode at the bottom of the screen:
- Press the Insert key again to go to replace the mode and override text.
- Press the Esc key to exit insert or replace.
- Type yy to copy a line.
- Type p to paste the line.
- Type dd to cut the line.
- Type :w to save any changes. Optionally, specify a filename:
- To save the file in editing text, type
vim.txt - Type
:qto exit Vim
Let's open the file again and do a small change:
:wq: Write and exit at the same time:q!: Exit without saving
Now you are familiar with these commands, we can do basic file editing directly from the command line. This is the bare minimum that anybody needs to know when working with Vim, and we will use this knowledge in the chapters to come.
We will also have an entire section about Vim, where we will go into more detail about being productive in the coolest terminal editor today!
Bash is probably the most commonly used shell. It has lots of features and powerful scripting capabilities, but when it comes to user interaction, zsh is better. Most of its power comes from the awesome framework oh-my-zsh. In this section, we will be installing zsh.
Let's get started with the oh-my-zsh framework and we will be looking at some basic configuration options:
- Open the terminator and type
sudo apt install zshto installzsh, as shown in the following image:
After installing it, go to this link, https://github.com/robbyrussell/oh-my-zsh, and follow the instructions for installing the oh-my-zsh framework. The installation process is a one-line command with curl or wget. Let's install it using both the command one by one:
Via curl:
sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"
Via wget:
sh -c "$(wget https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh -O -)"
You will see that the command is giving an error saying that git is not installed, so we need to install that too. The following command-line is used to install git:
sudo apt install git
Notice how easy it is to install software in Ubuntu. This is also a big productivity booster; every common software package we might need is already prepackaged in the remote software repository and it takes us just one command to add new software to our computer.
Now that we have git installed, let's run the command again. We can see that this time it's working successfully and it's bringing us to our new shell. Oh-my-zsh also changes the default shell to zsh.
After installation, the first thing to do is go pick a theme. To see all available themes, run this:
ls ~/.oh-my-zsh/themes
Time can be very useful, for example if you want to know how long a command took to execute and you didn't use the time utility to measure your command's total runtime. Then, you can check out the prompt and see the time when the command started and the prompt to know when it was finished, and thus you can calculate the total time.
To change the theme, open ~/.zshrc and modify the ZSH_THEME variable. Save the file and open a new terminal window. Let's initialize an empty git directory so we can see how the prompt looks. You can see we are on the master branch:
Let's create a file, say readme.md. The * in the prompt shows that the directory is not clean. We can verify this with the git status command:
You can see how it gets verified. After we've cleaned up the directory, the * is gone. If we change branch, the prompt shows that we are on the new branch.
Let's quickly create a demo. Run the following commands on your terminal:
git branch test git checkout test
You can now see the branch name in the prompt, and there are some other cool features that you might like to explore:
- Command completion: Start typing, for example, ip, and press Tab. We can see all the commands that start with IP and we can hit Tab again to start navigating through the different options. You can use the arrow keys to navigate and hit Enter for the desired command:
- Params completion: For example type
ls -and press Tab, and we can see here all the options and a short description for each. Press Tab again to start navigating through them and Enter to select.
- History navigation: Click on arrow up key to search in history, filtering by the string that is written before the cursor. For example, if I type
vimand press the arrow up key, I can see all the files opened with Vim in my history. - History search: Press Ctrl + R and start typing, and press Ctrl + R again to search the same occurrence in history. For example ~, and Ctrl + R to see all commands that have ~ in the string.
- Navigating: Here press Ctrl + arrow left/right to jump one word, Ctrl + W to delete one word, or Ctrl + U to delete the whole line.
- cd completion case insensitive: For example,
cd docwill expand intocd Documents. - cd directory completion: If you are lazy and want to specify only a few key letters in a path, we can do that too. For example,
cd /us/sh/zs+ Tab will expand intocd /usr/share/zsh. - Kill completion: Just type
killand Tab and you will see a list ofpidsto kill. From there you can choose which process to kill. - chown completion: Type
chownand tab to see a list of users to change owner to. The same applies to groups. - Argument expansion: Type
ls *and hit Tab. You see*expanded to all files and folders in the current directory. For a subset, typels Do*and press Tab. It will only expand to documents and downloads. - Adds lots of aliases: Just type alias to see a full list. Some very useful ones are:
.. - go up one folder … - go up two folders - - cd o the last directory ll - ls with -lh
To see a list of shortcuts, run the bindkey command. The terminal is one of the places where you will spend a lot time, so it's really important to master our shell and use it as efficiently as possible. Knowing good shortcuts and viewing relevant and condensed information, such as our prompt, can make our job much easier.