Shell Scripts
Shell scripts are text files that contain shell commands. Such files can be executed as if they were programs. A script can be in any language for which an interpreter exists, for example, Python, PHP, Perl, and so on. Similar to how a Python or Perl interpreter loads a program file and executes it, the Bash shell can load and execute shell scripts. However, before we address shell scripts, we need to visit some concepts about how programs are executed.
Shell Command Categories
We will now learn about the various categories of shell commands and how scripts work like any other command. There are four types of commands that can be invoked by name from the shell. These are listed as follows:
- Binary Executables: Also called executable files or binaries, these contain machine code, and provide most of the functionality of a system, for example, GUI programs such as a web browser, or CLI based programs such as
grep
. The Bash shell itself is an executable. The...