Tcl · version 8

Run Tcl 8 online

Tcl 8 — run it in a Firecracker microVM on ls-judge. Real toolchain, no wrapper.

Starter code

What you get in Tcl 8

Clicking "Run now" opens the playground with this exact code and a matching test case — passes on first Run.

tcl
Tcl 8
set n [gets stdin]
puts [expr {$n * 2}]
stdin →21
expected →42
How it runs

How ls-judge runs Tcl 8

Every submission is compiled and executed inside its own Firecracker microVM — the same isolation primitive AWS Lambda uses. No shared container, no shared kernel with other users' code. The Tcl 8toolchain shipped with the microVM is the real thing (not a browser-side emulation): syscalls behave the way they do in production, and the compile / runtime behaviour matches what you would see on your own machine with that version installed.

Feed stdin from the Tests panel, watch verdicts stream per test case over a WebSocket. Free to use, no sign-up, works from any browser.