![]() So if we use 2>1, we will only redirect stderr to a file called 1. We use &1 to mention to the shell that the destination file is a file descriptor and not a file name. The syntax for this will be: command > /dev/null 2>&1 There is another way of doing the same by redirecting stderr to stdout first, and then redirect stdout to /dev/null. cat -INCORRECT_OPTION > /dev/null 2>/dev/null We can use the file descriptor for stderr( =2) for this. Let us redirect the stderr to /dev/null, along with stdout. We need to take stderr into account as well. Why is this happening? This is because the error messages are coming from stderr, but we are only discarding output from stdout. We still get an output like this: cat: unrecognized option '-INCORRECT' Let’s try running a command incorrectly and pipe it’s output to /dev/null. You will not get any output since it is discarded! The only way is to use file redirections ( >, >, or /dev/null ![]() Since it is not an executable file, we cannot use piping using | operator to redirect to /dev/null. The file permissions are also set that anyone can read/write to it, but cannot execute it. This shows that this file has a size of 0 bytes, has zero blocks allocated to it. Size: 0 Blocks: 0 IO Block: 4096 character special fileĭevice: 6h/6d Inode: 5 Links: 1 Device type: 1,3Īccess: (0666/crw-rw-rw- ) Uid: ( 0/ root ) Gid: ( 0/ root ) This gives me an output of File: /dev/null This is a valid file, which can be verified using stat /dev/null This will return an End of File ( EOF) character if you try to read it using the cat command. Let’s take a look at understanding what it means, and what we can do with this file. This is a command-line hack that acts as a vacuum, that sucks anything thrown to it. This will discard anything written to it, and will return EOF on reading. Send us feedback about these examples./dev/null in Linux is a null device file. These examples are programmatically compiled from various online sources to illustrate current usage of the word 'black hole.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Steven Johnson, New York Times, 15 Mar. 2023 While building particle accelerators like the Large Hadron Collider, scientists seriously debated the possibility that activating the accelerator would trigger the creation of tiny black holes that would engulf the entire planet in seconds. Allison Parshall, Scientific American, 17 Mar. 2023 Besides the rich bounty of dust and heavy elements, the explosion might leave behind a black hole. 2023 Two black holes become two gigantic clouds of particles. Kyle Paoletta, Harpers Magazine, 29 Mar. 2023 Share Terrestrial bacteria can grow on extraterrestrial nutrients the black hole nearest Earth was discovered in the constellation Telescopium and X-ray experiments conducted at the European Synchrotron indicated that moisture is destroying The Scream. Jennifer Ouellette, Ars Technica, 30 Mar. 2023 The baby black hole would produce jets of highly energetic particles moving near the speed of light, powerful enough to pierce through the remains of the progenitor star, emitting X-rays and gamma rays. 2023 Detectors on Earth have detected the shorter, sharper waves generated by collisions of star-size black holes. Jackie Appel, Popular Mechanics, 31 Mar. 2023 Researchers are hoping the data gathered on this blast will provide insight into whether or not black holes actually give power back to the universe, rather than just swallowing everything up. Recent Examples on the Web Astronomers suspect the jets blasted out of the black hole that created the BOAT were narrower than usual.
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