SYSTEM(3S)              COMMAND REFERENCE              SYSTEM(3S)



NAME
     system - issue a shell command

SYNOPSIS
     system(string)
     char *string;

DESCRIPTION
     System causes the string to be given to sh(1sh) as input as
     if the string had been typed as a command at a terminal.
     The current process waits until the shell has completed,
     then returns the exit status of the shell.

DIAGNOSTICS
     Exit status 127 indicates the shell couldn't be executed.

CAVEATS
     It is very important to remember that system executes sh.
     This means that shell metacharacters such as `*' and `|' are
     interpreted, even when present in filenames.  This can cause
     undesirable results when system is used to execute commands
     with arguments provided by the user.

     Since system executes sh, the overhead of executing sh, such
     as copying the environment into shell variables, causes
     system to be slower than simply using fork and exec.

     For these reasons, it is best to use system in cases where
     the command to be executed contains shell variables and/or
     redirection and/or pipes, which are difficult to build in to
     a program.

SEE ALSO
     execve(2), fork(2), wait(2), and popen(3s).





















Printed 5/12/88                                                 1

%%index%%
na:312,82;
sy:394,389;
de:783,490;
di:1273,186;
ca:1459,1248;
se:2707,194;
%%index%%000000000108