This extension can start multiple subprocesses arbitrarily connected via pipes and scheme ports.
This example invokes tar to create an archive of some files and pipes the output through gpg for encryption. The encryption passphrase is given to gpg on file descriptor 3. The output of tar and gpg are saved.
(let ((passphrase "foobar") (tar-stderr #f) (gpg-stdout #f) (gpg-stderr #f)) (run-pipeline (pipeline:process "tar" (append '("-czf" "-") files) #f (pipeline:input-from-file 0 "/dev/null") (pipeline:output-to-pipe 1 'tar-out) (pipeline:output-to-port 2 (lambda (port) (set! tar-stderr (read-all port))))) (pipeline:process "gpg" (list "-o" outfile "--symmetric" "--passphrase-fd=3" "-") #f (pipeline:input-from-pipe 0 'tar-out) (pipeline:output-to-port 1 (lambda (port) (set! gpg-stdout (read-all port)))) (pipeline:output-to-port 2 (lambda (port) (set! gpg-stderr (read-all port)))) (pipeline:input-from-port 3 (lambda (port) (display passphrase port))))))
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