Bash stderr and stdout redirection failing

Question

I have a FORTRAN program output I want to redirect to file. I've done this before and use

$myprog.out>>out.txt 2>&1

and for some reason this is not working. I test it with a another simple test program

$myprog.test>>out.txt 2>&1

and it works

I run myprog.out and the output goes to screen as usual but redirecting it seems to fail! It was working and now seems to have stopped working. It's very strange. I commented out a few print statements that I no longer wanted, recompiled and then band redirect does not work.

There is clearly something different going on with my output but how to diagnose where it is going?

Answer 1

You probably need to flush your output. See for example this SO topic. How to do that depends on your compiler I guess. Because only Fortran 2003 Standard includes flush() statement and the ability to determine numbers that corresponds to stdout/stderr units.

However in gfortran (for example) you can use flush() intrinsic procedure with the equivalents of Unix file descriptors: UNIT=5 for stdin, UNIT=6 for stdout and UNIT=0 for stderr.

PROGRAM main

  PRINT *, "Hello!"
  CALL flush(6)
  CALL flush(0)

END PROGRAM main