SatDump writes to stderr via fwrite() with its custom logger. When
stderr is redirected to a pipe, C runtime fully buffers it. Neither
stdbuf nor bufsize settings help since SatDump doesn't use stdio for
output.
PTY (pseudo-terminal) makes SatDump think it's writing to a real
terminal, which disables buffering. Also strips ANSI escape codes
from the output and properly handles \r progress lines.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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