so here is the POC

this runs the commands without using fork. That means it can work on bare metal environments like tinygo and tamago

It has a very simple problem:
/tmp/tiny3283520552/builder407189277/src/bb.u-root.com/bb/bb rush
% date
2023/02/26 00:46:00 run /usr/bin/date
Sun Feb 26 00:46:00 UTC 2023
% rush
2023/02/26 00:46:03 run rush
% date
2023/02/26 00:46:05 run /usr/bin/date
/tmp/tiny3283520552/builder407189277/src/bb.u-root.com/bb/bb flag redefined: u
panic: /tmp/tiny3283520552/builder407189277/src/bb.u-root.com/bb/bb flag redefined: u

because of globals :-)

ok, with the latest
% date
2023/02/26 01:03:15 run /usr/bin/date
Sun Feb 26 01:03:15 UTC 2023
% date
2023/02/26 01:03:16 run /usr/bin/date
Sun Feb 26 01:03:16 UTC 2023
% date
2023/02/26 01:03:17 run /usr/bin/date
Sun Feb 26 01:03:17 UTC 2023
% date
2023/02/26 01:03:17 run /usr/bin/date
Sun Feb 26 01:03:17 UTC 2023
%

no more problems with flag.

Codecov Report

Patch coverage: 11.11% and project coverage change: -0.01 ⚠️

Comparison is base (5b46c23) 74.71% compared to head (24837df) 74.70%.

@@            Coverage Diff             @@
##             main    #2634      +/-   ##
==========================================
- Coverage   74.71%   74.70%   -0.01%     
==========================================
  Files         412      413       +1     
  Lines       41651    41653       +2     
==========================================
  Hits        31118    31118              
- Misses      10533    10535       +2     

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

Otherwise it works for me:

root@epiphyte:/tmp/tiny588138646/builder4051922320/src/bb.u-root.com/bb# ./bb rush
% date
2023/02/26 09:51:22 run /usr/bin/date
Sun Feb 26 09:51:22 UTC 2023