Most text editors can open files from a computer's command line shell. Here are 8 different text editor commands for opening a file:
IDLE (Python's Built-in Editor)
image source: IDLE documentation
emacs -nw file.txt
source: Stack Overflow user Anthon
start notepad++ file.py
source: W3 Schools
open -a TextEdit file.txt
source: Stack Overflow user robmathers
source: confirm blog
The ability to quickly pop open and view a file is essential. Ubuntu has the cat command to print a file's contents to the terminal screen also if you don't need to edit it. Tools like sed and awk are useful for command line file editing if you prefer to keep it in the terminal.
Want to read more about text editors? Check out my text editor file size comparison here.