CompTIA Linux+ Portable Command Guide: All the commands for the CompTIA XK0-004 exam in one compact, portable resource, 2nd Edition

Chapter 25. Given a scenario, deploy and execute basic BASH scripts

This chapter provides information and commands concerning the following topics:

Shell environments and shell variables

• PATH

• Global

• Local

• export

• env

• set

• printenv

• echo

#!/ bin/bash

Sourcing scripts

Directory and file permissions (chmod)

Extensions

Commenting (#)

File globbing

Shell expansions

• ${}

• $()

• ‘ ‘

Redirection and piping

Exit codes

• stderr

• stdin

• stdout

Metacharacters

Positional parameters

Looping constructs

• while

• for

• until

Conditional statements

• if

• case

Escaping characters

Shell Environments and Shell Variables

Shell variables are used to store information. This information is used to modify the behavior of the shell itself or external commands. The following table ...