Support "Run and Advance" behavior and "Run" button for shell scripts (.sh)

Request from a user to treat shell scripts more like R/Python scripts, wherein you can use Positron's run gestures to run a line at a time to step through the script execution. RStudio does support this, for all the reasons the author pointed out.

Discussed in https://github.com/posit-dev/positron/discussions/11442

^{Originally posted by tsukki1107 January 19, 2026}
Is your feature request related to a problem? Please describe. I am migrating from RStudio to Positron. In RStudio, shell scripts (.sh) have excellent support similar to R scripts:

Executing a line using Cmd+Enter (or Ctrl+Enter) automatically moves the cursor to the next line ("Run and Advance").

There is a visible "Run line/selection" button in the editor toolbar to execute the selected line(s).

Currently in Positron, Cmd+Enter sends the code to the terminal, but the cursor stays on the same line. Also, there is no dedicated "Run line/selection" button.

Describe the solution you'd like I would like to request:

"Run and Advance" behavior: An option or default where executing a line in a .sh file moves the cursor to the next line.

"Run" Button UI: A "Run" button in the editor toolbar for .sh files that triggers this "Run current line/selection" action, matching the UI for R and Python files.

Additional context This parity with RStudio would significantly improve the workflow for users who frequently rely on shell scripts for data processing pipelines and prefer interactive execution.

Start at the shell-script Cmd/Ctrl+Enter path and compare it with the existing R/Python run gestures and editor-toolbar actions. Verify how selected lines are sent to the terminal and how cursor advancement is handled. Done means .sh files support Run current line/selection from the toolbar and Run and Advance moves to the next line, matching the request.