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Guile Reference Manual

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38.10 Pipes

The following procedures provide an interface to the popen and pclose system routines. The code is in a separate "popen" module:

(use-modules (ice-9 popen))

Scheme Procedure: open-pipe command modes
Executes the shell command command (a string) in a subprocess. A pipe to the process is created and returned. modes specifies whether an input or output pipe to the process is created: it should be the value of OPEN_READ or OPEN_WRITE.

Scheme Procedure: open-input-pipe command
Equivalent to open-pipe with mode OPEN_READ.

(read-line (open-input-pipe "date"))
=> "Mon Mar 11 20:10:44 GMT 2002"

(waitpid WAIT_ANY)
=> (24160 . 0)

Scheme Procedure: open-output-pipe command
Equivalent to open-pipe with mode OPEN_WRITE.

Scheme Procedure: close-pipe port
Closes the pipe created by open-pipe, then waits for the process to terminate and returns its status value, See section waitpid, for information on how to interpret this value.

close-port (see section close-port) can also be used to close a pipe, but doesn't return the status.

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