17. Networking and Remote Access

This chapter applies Bash to network checks, downloads, secure file transfer, remote execution, and remote automation.

• Diagnostics: Use commands such as ping and curl to inspect connectivity.

• Retrieval: Download data and check responses before processing them.

• Transfer: Move files between systems with scp and rsync.

• Remote execution: Run commands over SSH while preserving safety and quoting.

• Automation: Coordinate remote checks and deployments across hosts.

Chapter Video

Linux Crash Course: Connecting to Linux Servers via SSH (15:54) by Learn Linux TV

Hosted on YouTube; property of its original creator, embedded here for educational reference only.

Learning Objectives

By the end of this chapter, you will be able to:

1. Use ping, curl, and wget for network inspection and retrieval.

2. Verify SSH host identity, configure authentication, and run remote commands.

3. Transfer files securely with scp and rsync.

4. Automate network and remote-system checks.

Chapter Flow

1. Network Commands: Ping, Curl, and Wget

2. Remote Execution with SSH

3. Secure File Transfer: SCP and Rsync

4. Network Automation

Glossary

#	Term	Explanation
1	Network diagnostic	A command or technique used to check network behavior.
2	ping	A command that tests whether a host responds to ICMP echo requests.
3	curl	A command-line tool for making URL-based requests.
4	wget	A command-line tool commonly used for downloading files.
5	HTTP status code	A numeric response code such as 200, 404, or 500.
6	Timeout	A maximum waiting period before a network operation fails.
7	Retry	A repeated attempt after a transient failure.
8	SSH	A secure protocol for remote login and command execution.
9	SSH key	A cryptographic credential used for SSH authentication.
10	Known hosts	The SSH record of host keys previously seen by the client.
11	Remote command	A command executed on another system through SSH.
12	Quoting boundary	The point where local shell expansion and remote shell expansion must be separated.
13	scp	A command for copying files over SSH.
14	rsync	A synchronization tool that copies only changed data when possible.
15	Trailing slash	A slash that changes whether rsync copies a directory itself or its contents.
16	Deployment	The process of copying and activating files or configuration on a target system.
17	Remote host	A system accessed over a network.
18	Connectivity check	A quick test that a network target is reachable.
19	API request	A structured network request to a service endpoint.
20	Monitoring script	Automation that checks remote systems and reports status.