「Transwiki:Bash Shell Scripting」の版間の差分

As we have seen, a command's return value, taken strictly, is just a small non-negative integer intended to indicate success or failure. Its real output is what it writes to the standard output stream. By default, text written to the standard output stream is printed to the terminal, but there are a few ways that it can be "captured" and used as the command's true return value.
When a sequence of commands are linked together in a pipeline, the output of each command is passed as input to the next. This is a very powerful technique, since it lets us combine a number of small utility programs to create something complex.