Unix script dev null

Best Regards, Sridhar M Quote:. Originally Posted by rrs. Hello All and a Happy New year to yous guys. I'm running the below command on my AIX box and it keeps giving me the message that the file doesn't exist. I know the file don't exist, but I don't want to see the error.

I apologize if this question has been answered else where or is too elementary. How are these two different? They both prevent output and error from being displayed.

Hi expert, May I know what is the difference between below cron tab entry? Maybe it's an stupid question but remeber I'm Junior.. I use command line to run programs, and some of them gives a lot of information when, for example, you open a window or other actions.

Whenever any command-line utility is run, it generates two outputs. The output goes to stdout and the error if generated goes to stderr. By default, both these data streams are associated with the terminal. For example, the following command will print out the string within the double quotation mark.

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. 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. Viewed k times. I'm reading an example bash shell script:! Redirect errors because this generates some if the archive does not exist. Then create a new compressed file. Improve this question.

JohnMerlino JohnMerlino 5, 11 11 gold badges 31 31 silver badges 37 37 bronze badges. Just a trick to avoid unnecessary output. I'm sure you could find more.