Hi Yifat,

>& is not valid bourne shell syntax (looks like csh to me), and /bin/sh -c (bourne shell) is what Perl uses in order to execute the  system command string on unix systems.

See this for the full scoop on system.

In /bin/sh redirection works like so:

ls > ls.out  -- Send stdout of ls to ls.out

mycmd > mycmd.out 2> mycmd.err -- Send stdout to mycmd.out, stderr to 
+mycmd.err

If you'd like stdout and stderr to go to the same location, use 
mycmd > mycmd.log 2>&1
[download]

It can get a lot fancier than that, see your local system documentation (man sh) or look here http://www.torget.se/users/d/Devlin/shell/man_sh.html.