difference between exec, system, fork, pipe, syscall and eval

abhi.nitk2003 has asked for the wisdom of the Perl Monks concerning the following question:

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Re: difference between exec, system, fork, pipe, syscall and eval by JavaFan (Canon) on Mar 19, 2010 at 15:44 UTC
`exec` replaces the current process with another one. `system` runs another program, wait for its completion. `fork` copies the current process; both the original and the copy continue from the same point. `pipe` sets up a pipe between two handles. `syscall` makes a low-level system call. `eval` executes (the string form will first compile) a piece of Perl code. I know these all are system built in function to creating a process. Uhm, you know wrongly.	[reply]
Re: difference between exec, system, fork, pipe, syscall and eval by ikegami (Patriarch) on Mar 19, 2010 at 15:00 UTC
exec, system, fork, pipe, syscall, eval BLOCK and eval EXRP By the way, only two of them create processes.	[reply]
Re: difference between exec, system, fork, pipe, syscall and eval by toolic (Bishop) on Mar 19, 2010 at 15:00 UTC
There are plenty of small examples in the free online documentation: exec, system, etc. Also, there are many more examples if you Super Search the Monastery. A small amount of effort goes a long way. See also: Tutorials -> Threads, Multi-Processing, and Inter-Process Communication	[reply]
Re: difference between exec, system, fork, pipe, syscall and eval by kennethk (Abbot) on Mar 19, 2010 at 15:03 UTC
The differences between these various elements are detailed in exec, system, fork, pipe, syscall and eval. You've also forgotten backticks, which is the method I need most often. Please note that `eval` does not invoke the operating system at all, rather invokes the Perl interpreter on the string you pass it. What are you trying to do?	[reply] [d/l]
Re: difference between exec, system, fork, pipe, syscall and eval by ssandv (Hermit) on Mar 19, 2010 at 23:01 UTC
You also forgot open. And this sounds like homework. It might be helpful if you clarified why this isn't something you can answer yourself with `perldoc`.	[reply] [d/l]
Re^2: difference between exec, system, fork, pipe, syscall and eval by kiruthika.bkite (Scribe) on Mar 20, 2010 at 05:11 UTC
- exec is used to execute the given process by replacing the current process. - If the given process get executed successfully then exec will not return the value. - exec returns the value in case of failure only. - System is also doing the same thing as exec but system returns value in both success and failure cases. - And parent process waits for the child process to complete. - System() runs the command through a shell,while exec() runs the command directly. - fork is used to create a new process(child process). - And it is returning the PID of child to parent and zero to child if the fork is successful. - The difference between the fork and exec is exec replaces the current process but fork doesn't. - pipe is used for communicating between two processes. - We can use both named and nameless pipes. - It returns open a pair of pipes. - In one end we can write. - And in another end we can read the content. - syscall is used to call the system call which is specified as a first argument. - Remaining elements are the arguments to the system call. For more details visit the following link also. Perl IPC	[reply]