![[Erlang Systems]](min_head.gif)
The functions in this module are operating system specific. Careless use of these functions will result in programs that will only run on a specific platform. On the other hand, with careful use these functions can be of help in enabling a program to run on most platforms.
Command = string() | atom() Executes Command in a command shell of the target OS and
returns the result as a string. This function is a replacement
of the previous unix:cmd/1; on a Unix platform they are
equivalent.
Examples:
LsOut = os:cmd("ls"), % on unix platform
DirOut = os:cmd("dir"), % on Win32 platform
find_executable(Name) -> Filename | false
find_executable(Name, Path) -> Filename | false
Name = string()Path = string()Filename = string()These two functions look up an executable program given its name
and a search path, in the same way as the underlying operating
system. find_executable/1 uses the current execution path (i.e.,
the environment variable PATH on Unix and Windows).
Path, if given, should conform to the syntax of execution
paths on the operating system.
The absolute filename of the executable program Name is
returned, or false if the program was not found.
List = list() of string Returns a list of all environement variables.
Each environment variable is a single string, containing the
name of the variable, followed by =, followed by the value.
getenv(VarName) -> Value | false
Varname = string() Value = string()Returns the Value of the environment variable VarName,
or false if the environment variable is undefined.
Value = string()Returns the process identifier of the current Erlang emulator
in the format most commonly used by the operating system
environment. Value is returned as a string containing the
(usually) numerical identifier for a process. On Unix, this is
typically the return value of the getpid() system
call. On VxWorks, Value contains the task id (decimal
notation) of the Erlang task. On Windows, the process id as
returned by the GetCurrentProcessId() system call is
used.
putenv(VarName, Value) -> true
Varname = string() Value = string()Sets a new Value for the environment variable VarName.
type() -> {Osfamily,Osname} | Osfamily
Osfamily = atom() = win32 | unix | vxworksOsname = atom()Returns the Osfamily and, in some cases, Osname of the current operating system.
On Unix, Osname will be same string that uname -s returns, but in lower case.
For instance, on Solaris 1 and 2, the atom sunos will be returned.
In Windows, Osname will be either nt (on Windows NT),
or windows (on Windows 95).
On VxWorks Osfamily alone is returned, i.e. the atom vxworks.
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Think twice before using this function.
Use the |
version() -> {Major, Minor, Release} | VersionString
Major = Minor = Release = integer()VersionString = string()Returns the operating system version. On most systems, this function returns a tuple, but a string will be returned instead if the system has versions which cannot be expressed as three numbers.
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Think twice before using this function.
If you still need to use it, always |