Mastering Bash

Messing around with stdin, stdout, and stderr

Well, if we tinker a little bit with the file descriptors and special characters we can have some nice, really nice, outcomes; let's see what we can do.

• x < filename: This opens a file in read mode and assigns the descriptor named a, whose value falls between 3 and 9. We can choose any name by the means of which we can easily access the file content through the stdin.
• 1 > filename: This redirects the standard output to filename. If it does not exist, it gets created; if it exists, the pre-existing data is overwritten.
• 1 >> filename: This redirects the standard output to filename. If it does not exist, it is created; otherwise, the contents get appended to the pre-existing data.
• 2 > filename