This is the third article in the “CLI tricks” series. This time we are going to cover UNIX-specific pipes, streams and redirections, explaining what they are for and how they can help us in every day console tasks.

Now that we have covered some of the minor improvements found in bash 4.x, we will begin looking at the more significant new features focusing on changes in the way bash 4.x handles expansions.

In this installment, we are going to look at a couple of commands that have been updated in bash 4.x

Bash functions, unlike functions in most programming languages do not allow you to return a value to the caller. When a bash function ends its return value is its status: zero for success, non-zero for failure. To return values, you can set a global variable with the result, or use command substitution, or you can pass in the name of a variable to use as the result variable.

It took me ages to learn bash redirection properly, and I still have to concentrate sometimes to keep my &s and my >s straight. Here's the lowdown in case you, too, have intermittent brain failure on this one.

The Bash shell is the default shell environment in most Linux distributions, including all flavours of Debian. One default feature of the Bash shell is to record a history of all the commands entered by a user in a log file called .bash_history, found in the user's home directory.

By and large, most Red Hat Linux systems will have Bash as the default shell. Bash is a darn great shell, but this article is about another equally great shell, called Z-Shell, that has most of the attributes of Bash, but in some cases goes the extra mile to give you the flexibility to customize your shell more than Bash allows.

It took me ages to learn bash redirection properly, and I still have to concentrate sometimes to keep my &s and my >s straight. Here's the lowdown in case you, too, have intermittent brain failure on this one. Bash has three standard file descriptors: stdin, stdout and stderr, which refer respectively to input, output and error output.

Here we go, bash scripting is nothing more then combining lots of UNIX commands
to do things for you, you can even make simple games in bash
(just UNIX commands) or as in normal cases, batch files to control things
in your computer.