If you’re working with the command line in Windows or the terminal in Linux and macOS, you know about the feature of the command-line history. You can access all previously issued commands with the arrow up or arrow down keys.
As a Python coder, you want to be able to control everything from your Python shell. This naturally leads to the following question.
Problem Formulation: How to get the entire command history in Python—all commands that have been executed in the interactive Python session?
Method 1: Python 3 One-Liner with readline.get_history_item()
readline module works in combination with Unix-like operating systems such as macOS and Linux. This one-liner is easy to copy and paste into your Python shell to access the command history in Python:
import readline; print('\n'.join([str(readline.get_history_item(i + 1)) for i in range(readline.get_current_history_length())]))
Method 2: Python 3 Multi-Liner with readline
This multi-liner does the same as the previous one-liner—it’s just more readable and less concise. 😉
import readline for i in range(readline.get_current_history_length()): print(readline.get_history_item(i + 1))
Method 3: Python 2 One-Liner with readline
Okay, some people may still use Python 2. In this case, you’ll need to slightly modify the previous one-liner to obtain:
import readline; print '\n'.join([str(readline.get_history_item(i + 1)) for i in range(readline.get_current_history_length())])
Method 4: Print File for Unix-Like OS
The following file contains the history:
~/.python_history. You can access it with the following command on macOS or Linux:
$ cat ~/.python_history
Note that you need to
quit() the interpreter for the current session history to be included in the file
Method 5: Write History Into a File
The readline module also provides a function
write_history_file() to write the command history into a file with name, say,
'python_command_history.py‘. Pass the desired filename into the function and Python will dump the Python commands into a new file with the given filename.
import readline readline.write_history_file('python_command_history.py')
Method 6: Use Up and Down Arrows If You’re Running Python Shell From Command Line
If you’ve opened a Python session from the command line, you can use up and down arrows to get the previous commands because Python uses the same history mechanism as the operating system:
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