The correct option is gsi -:d- Thanks, Marc, and I see it's in the Gambit manual, clearly enough: The `d' option sets various debugging options. The letter `d' is followed by a sequence of letters indicating suboptions. [...] `i' The REPL interaction channel will be the IDE REPL window (if the IDE is available).[...] `-' The REPL interaction channel will be standard input and standard output.[...] The default debugging options are equivalent to `-:dpqi1' But as I usual I'll carp that something this important should be explained at top level. Or is it not important? Don't folks `time' their long bg jobs? Anyway, I can't get it to work for gsc/gcc. This works fine: % m six.scm (time (pretty-print 6)) % export GAMBCOPT=d- % gsi six.scm > 13-73put % more 13-73put 6 (time (pretty-print 6)) 0 ms real time 0 ms cpu time (0 user, 0 system) no collections 104 bytes allocated no minor faults 5 major faults But I lose the `time' info with gsc/gcc: % gsc six % gcc -O2 -L. -I. six.c six_.c -lgambc % ./a.out > 13-73put % more 13-73put Now Brad, I think this is wrong: I think the manual may be in error; I think the time info goes to stderr, not stdout. If you're using csh or tcsh, you can try gsi -:- 6.scm >& six I don't know how to do it with bash or /bin/sh. Yeah, >& redirects both stderr & stdout in bash, and I tried that. But the local hotshot here said it was a stdin problem. Note how he realized it was a runtime problem, which I hadn't mentioned: FYI, the "Stopped" message in the line [1]+ Stopped nice ./73a.out 1>&13-73put means the process is trying to read, or otherwise access, stdin while detached. In a high-level language like Scheme, this can be reflect internal workings of the runtime support, rather than explicit instructions of your program. Thanks, Rico!