However, the owner or user with root privileges should be able to delete it, right? The permissions for group and others is r-x which means members of the group and other users can read and search the directory but cannot create or delete files in it. Note that write permission allows the owner to create or delete files in the directory. The owner has all the permissions rwx which means the owner of the directory can read, write and search the directory. The subsequent characters are for owner, group and others – 3 characters each, respectively. In the first column, the first character d denotes that /dev is a directory. Let’s check the permission of /dev directory: In order to delete a file, we need to have write permission on the directory in which the file is. Well, first let’s try to find out if we can delete it. So you want to see the consequences of deleting the black hole? :D Note that the redirection operator < is for input (stdin).įor example: In mail command, if we want to avoid email body, we can do so by using:Įxample: $ mail -s hello < /dev/null In other words, it will instantly send an EOF to the command/script so that it does not wait for input. We can provide a null or empty input to a command/script, if required We can empty a file (clear a file’s content) by redirecting output of /dev/null to it Hence, it comes handy when you run a command/script and it generates output or error that you want to ignore. Redirect stdout and stderr to file &> file
#UNINSTALL BLACKHOLE HOW TO#
In other words, you cannot change /dev/null Is it useful? How to use it?
You may write any amount of data to it, which will be immediately discarded, so its size will always remain 0 – Singularity? The cat command returned nothing and as per the stat command, its size did not change.Īs stated earlier, it discards anything written to it. What happens to the file’s size when we write data to it? Also, it’s good to note that the file’s read and write permission is enabled for everyone but it doesn't require execute permission. So, it's empty! What more can we know about the file?
This can be checked using test -c as well:Īs stated earlier, it just returns an EOF (end-of-file) when read. Yes and most of the things in Linux is a file but /dev/null is not a regular file – lets dig deeper.Ĭ in crw-rw-rw- tells us that it's a character special file, which means it processes data character by character. It’s a special file which is also referred to as null device - /dev/null So, it’s just a file? Something similar exists in the Linux universe as well - it discards anything written to it and when read, just returns an EOF (end-of-file). As per NASA, “A black hole is a place in space where gravity pulls so much that even light can not get out”.
0 kommentar(er)
