INTRO TO BASH SHELL on MAC part 2

In the part 1 of this learning topic you had one introductory approach to BASH in this part we will go deeper in the knowledge of BASH in MAC OS

Now that we know how to open a terminal window in a MAC we will need to confirm that we are really running bash on that window.
For that it is required to execute a simple command.

The command bellow will check if we are running bash.

echo $BASH

Notice that if you do not use the capitals in “BASH” you will not get the return.

If your output is not “/bin/bash” then install and enable BASH in your machine.

Command Arguments

A command is a word that is written in the shell.

In the previous example the command is “echo”.

Everything that comes after the command is called argument.

In the previous example “$BASH” is the argument for the command echo.

Options

If an argument starts with a  ” – ” then it is considered an option.

Examples:

  • ls -a
  • ls -l
  • ls -la

In this example the command is “ls” that corresponds to list and the -a is the option that instructs ls command to list all the files including the ones that are hidden, -l is the option that instructs the command to list the files in long format.

Help

The commands might have several options available. To list those options or to know how to use the commands we can call the manual for that command.

For that we use the command “man” and then as argument the name of the command that we wish to receive help for.

This will open the manual page for the specified command.

Space key will move down a page, “b” will move back a page.

Search will be done with the “/” and exit with “q”

Test this new commands and pay attention to the differences in the output.

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