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(m4.info)Syscmd

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Executing simple commands
=========================

   Any shell command can be executed, using `syscmd':

     syscmd(SHELL-COMMAND)

which executes SHELL-COMMAND as a shell command.

   The expansion of `syscmd' is void, _not_ the output from
SHELL-COMMAND!  Output or error messages from SHELL-COMMAND are not
read by `m4'.  Note: Esyscmd if you need to process the command
output.

   Prior to executing the command, `m4' flushes its output buffers.
The default standard input, output and error of SHELL-COMMAND are the
same as those of `m4'.

   The builtin macro `syscmd' is recognized only when given arguments.