exec
executes a command and never returns.
It's like a return statement in a function.
If the command is not found exec returns false.
It never returns true, because if the command is found it never returns at all.
There is also no point in returning STDOUT, STDERR or exit status of the command.
You can find documentation about it in perlfunc,
because it is a function.
system
executes a command and your Perl script is continued after the command has finished.
The return value is the exit status of the command.
You can find documentation about it in perlfunc.
backticks
like system executes a command and your perl script is continued after the command has finished.
In contrary to system the return value is STDOUT of the command.
qx// is equivalent to backticks.
You can find documentation about it in perlop, because unlike system and execit is an operator.
Other ways
What is missing from the above is a way to execute a command asynchronously.
That means your perl script and your command run simultaneously.
This can be accomplished with open.
It allows you to read STDOUT/STDERR and write to STDIN of your command.
It is platform dependent though.
There are also several modules which can ease this tasks.
There is IPC::Open2 and IPC::Open3 and IPC::Run, as well as
Win32::Process::Create if you are on windows.
Here is how to solve it on Mac OS X v10.7 (Lion) or Cygwin (Windows 10):
Add the following lines to your bashrc or bash_profile file on the host machine:
# Setting for the new UTF-8 terminal support in Lion
export LC_CTYPE=en_US.UTF-8
export LC_ALL=en_US.UTF-8
If you are using Z shell (zsh), edit file zshrc:
# Setting for the new UTF-8 terminal support in Lion
LC_CTYPE=en_US.UTF-8
LC_ALL=en_US.UTF-8
Best Answer
The
cdcommand changes the current directory of a shell process; the Perlchdirfunction changes the current directory of a Perl process. They're exactly the same thing, just spelled differently.