topic Re: Redirect output to /dev/null in Operating System - HP-UX

Redirect output to /dev/null

hpuxrox — Wed, 03 Mar 2004 08:32:25 GMT

Hi,

I am looking for examples on how to redirect output to /dev/null. Currently, we use

> /dev/null 2>&1

But I though I remember a shorter version of this with two && in the syntax?

Any of you gurus know the syntax?

Re: Redirect output to /dev/null

Victor BERRIDGE — Wed, 03 Mar 2004 08:47:18 GMT

Hi,
I dont see how with &&: && means what follows (&&) will be executed only if the preceding instructions complete without errors (return a 0 value)

All the best
Victor

Re: Redirect output to /dev/null

Mark Grant — Wed, 03 Mar 2004 08:55:07 GMT

No, your syntax is correct. You can not use &&

Re: Redirect output to /dev/null

hpuxrox — Wed, 03 Mar 2004 08:56:32 GMT

maybe it was &>- or something to that extent

Re: Redirect output to /dev/null

Geoff Wild — Wed, 03 Mar 2004 09:05:37 GMT

That is the correct way:

>/dev/null 2>&1

Rgds...Geoff

Re: Redirect output to /dev/null

hpuxrox — Wed, 03 Mar 2004 09:07:06 GMT

There is a shorter version of the syntax, Ill keep looking in my notes. thanks

Re: Redirect output to /dev/null

MarkSyder — Wed, 03 Mar 2004 09:23:34 GMT

If you find it could you please share it with us? I for one am ingrigued!

Mark Syder (like the drink but spelt different)

Re: Redirect output to /dev/null

Mark Grant — Wed, 03 Mar 2004 09:28:13 GMT

Yates,

I hope you have a lot of patience because you will be studying those notes for some time.

How much shorter can it be! You need to have the "/dev/null" in there somewhere which leaves us 6 compulsory characters if we are also re-direct the standard error. Even you reduce this syntax by 50% you are only going to save three characters. However, if you like, do this

"ln /dev/null /n"

Thereafter, your syntax could be

>/n 2>&1

This gets it much shorter.

Re: Redirect output to /dev/null

Michael Schulte zur Sur — Wed, 03 Mar 2004 10:09:16 GMT

Hi,

Yates is right. Ih ksh you find:
<&- The standard input is closed. The standard output is closed using >&-

never paid any attention to that.

greetings

Michael

Re: Redirect output to /dev/null

Michael Schulte zur Sur — Wed, 03 Mar 2004 10:14:27 GMT

One more,

this still would be
command &>- 2>&1

greetings,

Michael

Re: Redirect output to /dev/null

Mark Grant — Wed, 03 Mar 2004 10:17:11 GMT

closing standard input and closing standard output is not the same as redirecting to /dev/null.

Re: Redirect output to /dev/null

Michael Schulte zur Sur — Wed, 03 Mar 2004 10:24:56 GMT

Mark,

I see, what you mean. a programme that does get it's stdout closed might abort or burden the cpu.

Michael

Re: Redirect output to /dev/null

Mark Grant — Wed, 03 Mar 2004 10:44:08 GMT

Also, it doesn't close the standard error so this is NOT a substitute syntax for >/dev/null 2>&1.