Unix device null

Microsoft Windows is a group of many GUI based operating systems developed and offered. Select your default language. If you have multiple languages. In iTunes, choose Preferences, then click Devices. From here, you can right-click on the. Essentially all the output from the command would be redirected to the null device. It simply silences any sort of output including error from the command.

They are just sent to ' nowhere ' and forgotten. This is a way of running programs and making sure they produce NO output and will never be seen on the command line or in a log file. I see this type of question quite a bit Here is some handy information from the ABSG:. It is listed as "An in-depth exploration of the art of shell scripting " and I absolutely agree. It is a terrific resource and has tons of answers to all sorts of crazy situations. Here are a few I have found useful:. Sign up to join this community.

The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 7 years, 10 months ago. Active 4 months ago. Here, the output is stored in stdout. As the previous command ran successfully, the exit status is 0. Otherwise, the exit status will be different. What happens when you try to run an invalid command? Now, we need to know about the file descriptor. In the UNIX ecosystem, these are integer values assigned to a file.

Using the file descriptor 1 and 2 in this situation , we can redirect the stdout and stderr to other files. For starter, the following example will redirect the stdout of the echo command to a text file. Since messages and wtmp are regular files rather than, for example, device nodes , they are turned into blank files i.

The -n flag is required, or echo writes a newline character. This always works in bash. But jlliagre is right that echo -n should be avoided for a truly portable shell script, as it's not required to work. The echo -n way is equivalent in its effects but arguably is a better solution, in that it's simpler.

Although this should be expected to improve performance, that's not the benefit--not when just running a couple of these commands by hand, anyway. Instead, the benefit is that it's easier to understand what's going on. There is a reason to do it like this: the file is NOT removed from the system. If you would rm it and then do a touch messages the permissions might be wrong and if just after the rm something would want to write to the file it would be gone and error out.

Depending on how the software is created it could crash. Eliah Kagan's reply suggests the better approach which is using echo -n instead. With most shells but not the csh based ones , you can go even further and remove the no-op command ' : ' :. It will redirect the output of command to file mentioned after it instead of standard output device, truncating or overwriting file's contents.

After executing this command, "demo. Ubuntu Community Ask! Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.