Add an "unbuffered" argument to shell functions

[javierggt]

Description

Add an "unbuffered" argument to shell functions, which causes the output to be logged as it arrives instead of all at the end.

Some of the changes I had in the runasp repo were actually not specific to the aspect pipeline. They were changes to be able to see output in real time (to check things were working right away). Instead of making them there, better to make them here.

Interface impacts

Testing

Unit tests

Unit tests include new tests for the new feature (3 tests parametrized by 2, 6 new tests total).

• Mac
• Linux

jgonzale ska_shell $ git rev-parse HEAD
a96d9e519590660e208111ca0b3b478612cf144b
jgonzale ska_shell $ pytest ska_shell
========================================================================================= test session starts =========================================================================================
platform linux -- Python 3.13.11, pytest-9.0.2, pluggy-1.6.0
rootdir: /proj/sot/ska/jgonzalez/git
configfile: pytest.ini
plugins: anyio-4.12.1, timeout-2.4.0
collected 30 items                                                                                                                                                                                    

ska_shell/tests/test_shell.py ..............................                                                                                                                                    [100%]

========================================================================================= 30 passed in 3.83s ==========================================================================================

Independent check of unit tests by Jean

• linux

jeanconn-kady> pytest
============================= test session starts ==============================
platform linux -- Python 3.13.11, pytest-9.0.2, pluggy-1.6.0
rootdir: /proj/sot/ska/jeanproj/git
configfile: pytest.ini
plugins: anyio-4.12.1, timeout-2.4.0
collected 30 items                                                             

ska_shell/tests/test_shell.py ..............................             [100%]

============================== 30 passed in 4.58s ==============================
jeanconn-kady> git rev-parse HEAD
a96d9e519590660e208111ca0b3b478612cf144b

Functional tests

Tests are covered in unit tests, but if you want to see it in action, run this in one terminal while you tail -f test.log on another terminal:

import ska_shell

cmd = """echo 1
sleep 1
echo 2
sleep 1
echo 3
sleep 1
echo 4
sleep 1
echo 5
sleep 1
echo 6
sleep 1
echo 7
"""
with open("test.log", "w") as fh:
    ska_shell.tcsh_shell(cmd, logfile=fh, unbuffered=True)

[jeanconn]

Looks good to me.