File: m4.info,  Node: Shell commands,  Next: Miscellaneous,  Prev: Arithmetic,  Up: Top

13 Macros for running shell commands
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There are a few builtin macros in ‘m4’ that allow you to run shell
commands from within ‘m4’.

   Note that the definition of a valid shell command is system
dependent.  On UNIX systems, this is the typical ‘/bin/sh’.  But on
other systems, such as native Windows, the shell has a different syntax
of commands that it understands.  Some examples in this chapter assume
‘/bin/sh’, and also demonstrate how to quit early with a known exit
value if this is not the case.

* Menu:

* Platform macros::             Determining the platform
* Syscmd::                      Executing simple commands
* Esyscmd::                     Reading the output of commands
* Sysval::                      Exit status
* Mkstemp::                     Making temporary files