On Sat, Aug 27, 2011 at 8:38 AM, ashwin kesavan <[email protected]> wrote: > On 19 August 2011 18:57, Prasanna Venkadesh <[email protected]> wrote: >> On Fri, Aug 19, 2011 at 5:23 PM, Sathia S <[email protected]> wrote: >>> >>> > espeak 'hi' > /dev/null 2>&1 >> >> >> Thanks all for helping me out. The above thing works perfect. and can anyone >> give me explanation of what it does? One is it redirects to /dev/null and >> what does 2>&1 really does? >
I will explain. $ ls > /dev/null 2>&1 is the Bourne/ksh syntax for redirecting both stdout and stderr to /dev/null /dev/null is a construct to ignore output This is the way it is told to the shell. Redirect fd 1 to somewhere, then redirect fd 2 to fd 1( 2>&1) The left hand side is without '&', say 1> /dev/null or 2>/dev/null But the right hand side is written with an '&' to mean: Instead of to the file foo in 2>foo, redirect to the fd with 2>&1 So this means redirect fd 2 to fd 1 Instead if you write 2>1 it will redirect to a file called 1 -Girish -- G3 Tech Networking appliance company web: http://g3tech.in mail: [email protected] _______________________________________________ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
