Frequently Asked Questions#
A collection of commonly-asked questions concerning Bluesky.
How to install Bluesky?#
How to start a Bluesky session?#
See Getting Started
How to create an alias to start a bluesky session?#
There are several ways to create an alias to start a bluesky session. One is described here.
How to create an alias to activate the bluesky environment?#
In this section: Create an alias to activate the bluesky environment, look for become_bluesky.
In python, what are classes, objects, methods and instances?#
A class is like a blueprint or a template that defines the characteristics and behaviors of a particular type of object. For example, we can define a Dog class that includes attributes such as breed, age, and name, as well as behaviors such as barking and wagging its tail.
An object is an instance of a class. So, if we have a Dog class, we can create objects of that class, such as “Fido” and “Buddy”. Each object of the Dog class will have its own set of attributes, such as “Fido” being a Golden Retriever and “Buddy” being a Chihuahua, and methods, such as “Fido” barking loudly and “Buddy” wagging its tail.
An instance is a specific occurrence of an object created from a class. For example, with our Dog class, we can create an instance of that class called “my_dog” with specific attributes and behaviors.
A method is a function that is defined in a class and can be called on an object of that class. For example, the “bark” method defined in the Dog class can be called on the object “my_dog” to make it bark.
For more details:
What is bash?#
Bash is a type of shell, which is a program that provides a user interface for accessing the operating system’s services. To determine if you’re using bash, you can open up a terminal on your computer and type echo $SHELL. If the output is /bin/bash or something similar, then you’re using the bash shell.
If bash is not your default shell, type bash in a terminal and press Enter to start a new instance of the bash shell. You should see a new prompt indicating that you’re now using the bash shell. You can now type in bash commands. Note that any changes you make to your environment variables or other system settings within this bash session will only apply to this session and will not persist after you close the session. To change your default shell, contact your IT support.
What does the (~) mean in a path?#
The tilde (~) character represents the current user’s home directory. This is a shortcut that can be used to specify file paths without having to type out the entire path to the home directory.
How to understand a timestamp?#
Timestamps are floating point numbers offset from a fixed reference (1970-01-01 00:00 UTC). Convert that to a format for humans using the datetime package (assuming the local time zone, in this case “US/Chicago”):
1In [1]: import datetime
2
3In [2]: datetime.datetime.fromtimestamp(1685123274.1847932)
4Out[2]: datetime.datetime(2023, 5, 26, 12, 47, 54, 184793)
5
6In [3]: str(datetime.datetime.fromtimestamp(1685123274.1847932))
7Out[3]: '2023-05-26 12:47:54.184793'