| 2!:0 y |
Host. The list y is executed by the host system,
and the result is returned. For example, 2!:0 'dir *.exe'.
Not available for Windows or Macintosh.
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| 2!:1 y |
Spawn. Like 2!:0,
but yields '' without waiting for the host to finish.
Any output is ignored. For example, 2!:1 can be used
to invoke a text-editor. Not available for Windows or Macintosh.
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| 2!:2 y |
Host IO. (Unix only.) The host command line y
is passed to /bin/sh for processing, connecting two file numbers
to the command's standard input and output. The result is
a 3-element list of the process id of the task started and the
file numbers associated with its standard input and output.
These file numbers also appear in the result of 1!:20.
In this case, instead of appearing with a name they appear
with the command line, prefixed by > (standard input)
or < (standard output). The files associated with
the process should be closed with 1!:22 when no longer in use.
See also 2!:3 for a verb to wait for processes to complete.
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| 2!:3 y |
Wait. (Unix only.) Wait for process id y
to terminate. The result is the status code returned by the process.
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| 2!:4 y |
Command Line. When J is used as a shell, the result
of 2!:4 is a boxed list representing command line.
The first element is the name of the shell script itself;
subsequent elements are the arguments, if any.
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| 2!:5 y |
Getenv. The value of the shell environment variable
named y. If the named variable is undefined,
the result is 0.
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| 2!:55 y |
Terminate Session. y is an integer return code
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