NAME
system —
pass a command to the shell
LIBRARY
library “libc”
SYNOPSIS
#include
<stdlib.h>
int
system(const
char *string);
DESCRIPTION
Thesystem()
function hands the argument string to the command
interpreter sh(1). The calling process waits for the shell to finish executing the
command, ignoring SIGINT and
SIGQUIT, and blocking SIGCHLD.
If string is a
NULL pointer,
system()
will return non-zero, if the command interpreter is available, or zero if
none is available. Otherwise, system() returns the
termination status of the shell in the format specified by
waitpid(2).
RETURN VALUES
If a child process cannot be created, or the termination status of
the shell cannot be obtained, system() returns -1
and sets errno to indicate the error. If execution of
the shell fails, system() returns the termination
status for a program that terminates with a call of
exit(127).
SEE ALSO
STANDARDS
The system() function conforms to
ANSI X3.159-1989 (“ANSI C89”)
and IEEE Std 1003.2-1992
(“POSIX.2”).
CAVEATS
Never supply the system() function with a
command containing any part of an unsanitized user-supplied string. Shell
meta-characters present will be honored by the
sh(1)
command interpreter.