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call-system-showing-output Function


Executes a command by a shell or directly by the underlying Operating System and show the output.




call-system-showing-output command &key current-directory prefix show-cmd output-stream wait shell-type kill-process-on-abort => status, output-string

A string, a list of strings, a simple-vector of strings, or nil.
A string. Supported only on Microsoft Windows.
A string.
A boolean.
An output stream or nil, t or :tty.
A boolean.
A string. Supported only on non-Windows platforms.
A generalized boolean.
The exit status of the invoked shell or process.
A string or nil.

The function call-system-showing-output is an extension to call-system which allows output to be redirected. On non-Windows platforms this means it can be redirected to places other than the shell process from which the LispWorks image was invoked. call-system-showing-output therefore allows the user to, for example, invoke a shell command and redirect the output to the current Listener window.

command is interpreted as by call-system. On Microsoft Windows there is one difference: when command is a list or vector and the executable (that is, the first element of the sequence command) in call-system-showing-output is not a GUI application, LispWorks hides the first window, which is the console that the executable will normally open. Note that for a non-direct command (that is, a string) LispWorks always hides the first window (which is the console) in both call-system and call-system-showing-output.

On Microsoft Windows current-directory is the lpCurrentDirectory argument passed to CreateProcess. If this is not supplied, the pathname-location of the current-pathname is passed.

prefix is a prefix to be printed at the start of any output line. The default value is "; ".

show-cmd specifies whether or not the cmd invoked will be printed as well as the output for that command. If t then cmd will be printed. The default value for show-cmd is t.

output-stream specifies where the output will be sent to. If output-stream is an output stream, the output is written to it. If output-stream is t, the output is written to *standard-output*. If output-stream is nil, the output is collected as a string, and returned as a second value output-string. If output-stream is :tty, call-system-showing-output behaves like call-system. The default value is *standard-output*.

If wait is true, call-system-showing-output does not return until the process has exited. If nil, call-system-showing-output returns immediately and no output is shown. The default for wait is t.

shell-type is a string naming a UNIX shell. The default is "/bin/sh".

If kill-process-on-abort is true, then when call-system-showing-output is aborted the process is killed. The default value of kill-process-on-abort is nil.

On non-Windows platforms, the command line arguments and environment variables are encoded as specfied in 27.14.1 Encoding of file names and strings in OS interface functions.

call-system-showing-output returns the exit status of the shell invoked to execute the command on non-Windows platforms, or the process created on Microsoft Windows.


On Linux:

CL-USER 1 > (sys:call-system-showing-output "pwd" :prefix "***")
CL-USER 2 > (sys:call-system-showing-output "pwd" :prefix "&&&" :show-cmd nil)

On Microsoft Windows:

CL-USER 223 > (sys:call-system-showing-output
                        "cmd /c type hello.txt"
                        :prefix "***")
***cmd /c type hello.txt
***Hi there
CL-USER 224 > (sys:call-system-showing-output
                        "cmd /c type hello.txt"
                        :prefix "&&&"
                        :show-cmd nil)
&&&Hi there
See also


LispWorks® User Guide and Reference Manual - 01 Dec 2021 19:31:02