How to use the command xonsh (with examples)

Xonsh is a Python-powered, cross-platform, Unix-gazing shell. It allows users to write and mix sh/Python code in the Xonsh shell, providing a powerful and flexible environment for shell scripting and interactive shell sessions. This article will illustrate various use cases of the Xonsh command, along with their code, motivation, explanation, and example output.

Use case 1: Start an interactive shell session

Code:

xonsh

Motivation:

Starting an interactive shell session with Xonsh allows users to directly execute commands and scripts, interact with the shell environment, and make use of the shell’s features and capabilities.

Explanation:

The xonsh command starts an interactive Xonsh shell session in the terminal. By running this command, users can directly enter and execute commands in the shell environment.

Example Output:

xonsh: Welcome to the Xonsh shell!
Version: 0.9.27

Use case 2: Execute a single command and then exit

Code:

xonsh -c "command"

Motivation:

Executing a single command and then exiting is useful when you only need to run a specific command without entering an interactive shell session. This allows for executing Xonsh commands within scripts or running ad-hoc commands from the command line.

Explanation:

The xonsh -c "command" command executes the specified command within the Xonsh shell environment and then exits. The -c option tells Xonsh to run the provided command and terminate the shell session.

Example Output:

Suppose we want to print the current date within the Xonsh shell:

xonsh -c "python -c 'import datetime; print(datetime.datetime.now().date())'"

Output:

2022-12-21

Use case 3: Run commands from a script file and then exit

Code:

xonsh path/to/script_file.xonsh

Motivation:

Running commands from a script file is useful for executing a series of commands or automating tasks without manually entering each command in the shell.

Explanation:

The xonsh path/to/script_file.xonsh command runs the specified script_file.xonsh script within the Xonsh shell environment and then exits. This is particularly useful when you want to execute multiple commands or a set of complex instructions stored in a script file.

Example Output:

Suppose we have a script file script.xonsh containing the following commands:

import datetime
print(datetime.datetime.now().date())
print("Hello, world!")

Running the script with Xonsh:

xonsh script.xonsh

Output:

2022-12-21
Hello, world!

Use case 4: Define environment variables for the shell process

Code:

xonsh -Dname1=value1 -Dname2=value2

Motivation:

Defining environment variables for the shell process allows you to set specific values for variables that can be accessed and used within Xonsh commands and scripts.

Explanation:

The xonsh -Dname1=value1 -Dname2=value2 command defines environment variables for the Xonsh shell process. The -D flag followed by name=value assigns the value value1 to the variable name1 and value2 to the variable name2 within the shell environment.

Example Output:

Suppose we want to define two environment variables, NAME and AGE, within the Xonsh shell:

xonsh -DNAME=John -DAGE=30

Output:

xonsh: Welcome to the Xonsh shell!
Version: 0.9.27
echo $NAME
John
echo $AGE
30

Use case 5: Load the specified .xonsh or .json configuration files

Code:

xonsh --rc path/to/file1.xonsh path/to/file2.json

Motivation:

Loading configuration files allows you to customize the behavior of the Xonsh shell by specifying custom settings, aliases, environment variables, or other configurations.

Explanation:

The xonsh --rc path/to/file1.xonsh path/to/file2.json command loads the specified .xonsh and .json configuration files when starting an interactive Xonsh shell. This enables users to customize their shell environment according to their requirements.

Example Output:

Suppose we have a configuration file config.xonsh containing the following commands:

$FAVORITE_COLOR = "blue"

Running Xonsh with the configuration file:

xonsh --rc config.xonsh

Output:

xonsh: Welcome to the Xonsh shell!
Version: 0.9.27
echo $FAVORITE_COLOR
blue

Use case 6: Skip loading the .xonshrc configuration file

Code:

xonsh --no-rc

Motivation:

Skipping the loading of the .xonshrc configuration file can be useful when you want to start a clean Xonsh shell without any custom configurations or settings.

Explanation:

The xonsh --no-rc command starts a clean Xonsh shell session without loading the .xonshrc configuration file. This ensures that no custom settings, aliases, or environment variables defined in the .xonshrc file are loaded.

Example Output:

Running Xonsh without loading the .xonshrc configuration file:

xonsh --no-rc

Output:

xonsh: Welcome to the Xonsh shell!
Version: 0.9.27
echo $FAVORITE_COLOR
NameError: name 'FAVORITE_COLOR' is not defined

Conclusion:

The Xonsh command provides a versatile and powerful shell environment for executing commands, running scripts, and customizing the shell’s behavior. Whether you need to perform ad-hoc tasks, automate tasks with scripts, or customize the shell environment, the various use cases of the Xonsh command demonstrate its flexibility and usefulness.