07-17-2013
Looping with wait in UNIX
Hello Gurus ,
Could you help me with my below requirement
In my script I will start a process ,it takes some time to complete the process.After completion it will create a file
after that I have to restart the process again
The number of time it will be done will vary but that count we should know before
so here is the algorithm
for in 1...count
delete indicator file
step 1 start process
step 2 check indicator file exist [ denotes process completed ]
no then sleep for 30 second
go to step 2
else
go to step 1 [run the process again ]
do this until the for loop completed
Could anyone please give me the code or suggestion how to procees
Your help is very much appreciated
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system(3) Library Functions Manual system(3)
NAME
system - Executes a shell command
LIBRARY
Standard C Library (libc.so, libc.a)
SYNOPSIS
#include <stdlib.h>
int system(
const char *string);
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
system(): XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
PARAMETERS
Specifies a valid sh shell command.
If string is NULL (0), the system() function tests the accessibility of the sh command interpreter.
If string is not NULL, the system() function passes the parameter to the sh command, which interprets string as a command and exe-
cutes it.
DESCRIPTION
The system() function passes the string parameter to the sh command, which interprets string as a command and executes it.
The system() function invokes the fork() function to create a child process that in turn uses the exec function to run sh, which interprets
the shell command contained in the string parameter. The current process waits until the shell has completed before returning.
RETURN VALUES
If the string parameter is NULL, the system() function returns 0 if it is unable to access the command interpreter or a non-zero value if
sh is accessible.
If the string parameter is not NULL, upon successful completion by sh, the system() function returns the exit status of the shell process
in the form that wait(2) returns. Otherwise, the system() function returns a value of -1 and sets errno to indicate the error.
Exit status 127 indicates that the shell could not be executed.
Note that the exit status should only be interpreted using the macros described in wait(2) and defined in the sys/wait.h header file.
ERRORS
The system() function sets errno to the specified values for the following conditions: The status of the child process created by system()
is no longer available.
In addition, the system() function may set errno values as described by fork().
RELATED INFORMATION
Functions: exec(2), exit(2), fork(2), wait(2)
Commands: sh(1)
Standards: standards(5) delim off
system(3)