FreeLevel 1 · Foundations

Linux and Networking Basics

Every cloud and DevOps job assumes you can work on a Linux server. In this course you learn by investigating one: Tallybook's web server, prod-web-01, on the day its app slowed to a crawl. You'll run real shell commands in Google Colab: read and search logs with grep, cut, sort and uniq; rebuild the outage's timeline with awk; read file permissions and find secrets anyone could read; spot a process that shouldn't be running and a disk about to fill; follow an SSH brute-force attack through the authentication log to a successful break-in; audit firewall rules with IP addresses, CIDR blocks and ports; read DNS records and HTTP status codes; and write shell scripts and cron jobs that would have caught every problem. No Linux experience is needed. Every command and output in the lessons is checked by running it.

About 7 hours
10 modules
1 badge
Final project
Optional verified certificate

Curriculum

01The Command LineWhat the Linux shell is, how to run commands in Google Colab, and the first commands every engineer uses to look at files on a server: downloading, listing, counting and reading the start and end of files.10 min
02Finding Things in TextSearch logs with grep, combine commands with pipes, and count and rank with cut, sort, uniq and wc, to answer questions about a day of web traffic in one line each.15 min
03awk for ColumnsUse awk to filter rows by a column's value, add up and average columns, and count by time, and rebuild the timeline of the month-end outage from the access log.15 min
04Files and PermissionsRead Linux file permissions (owner, group, others; read, write, execute), translate them to numbers like 644 and 600, and find the files on Tallybook's server that anyone could read or change.25 min
05Processes, Memory and DiskRead process lists to see what a server is busy doing, check disk space with df and du, find what's filling a disk, and know what to do about a process that shouldn't be there.15 min
06SSH and the Auth LogHow engineers log in to servers with SSH, why keys beat passwords, and how to read the authentication log to find brute-force attacks, a successful break-in and what the intruder did next.25 min
07IP Addresses and PortsUnderstand IP addresses, private and public ranges, CIDR blocks and ports, and audit a set of firewall rules to find which services are open to the whole internet.25 min
08DNS and HTTPHow a name like app.tallybook.example becomes an address (DNS records, TTLs and common mistakes), and how HTTP requests, methods and status codes work, read from a real zone file and access log.25 min
09Shell Scripts and CronTurn commands into a reusable script with variables, conditions and exit codes, run it on a schedule with cron, and build a small health check that would have raised the alarm on 31 August.25 min
10Final ProjectPlan your final project, a full investigation of Tallybook's web server from its logs and command output, with a timeline, findings, fixes and the scripts that would have caught each problem.20 min
Final assessmentPass it (60% or more) to earn the Linux and Networking Basics course completion badge.

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Linux and Networking Basics

About 7 hours

10 modules

1 badge

Final project

Optional verified certificate

Curriculum

01The Command LineWhat the Linux shell is, how to run commands in Google Colab, and the first commands every engineer uses to look at files on a server: downloading, listing, counting and reading the start and end of files.10 min

02Finding Things in TextSearch logs with grep, combine commands with pipes, and count and rank with cut, sort, uniq and wc, to answer questions about a day of web traffic in one line each.15 min

03awk for ColumnsUse awk to filter rows by a column's value, add up and average columns, and count by time, and rebuild the timeline of the month-end outage from the access log.15 min

04Files and PermissionsRead Linux file permissions (owner, group, others; read, write, execute), translate them to numbers like 644 and 600, and find the files on Tallybook's server that anyone could read or change.25 min

05Processes, Memory and DiskRead process lists to see what a server is busy doing, check disk space with df and du, find what's filling a disk, and know what to do about a process that shouldn't be there.15 min

06SSH and the Auth LogHow engineers log in to servers with SSH, why keys beat passwords, and how to read the authentication log to find brute-force attacks, a successful break-in and what the intruder did next.25 min

07IP Addresses and PortsUnderstand IP addresses, private and public ranges, CIDR blocks and ports, and audit a set of firewall rules to find which services are open to the whole internet.25 min

08DNS and HTTPHow a name like app.tallybook.example becomes an address (DNS records, TTLs and common mistakes), and how HTTP requests, methods and status codes work, read from a real zone file and access log.25 min

09Shell Scripts and CronTurn commands into a reusable script with variables, conditions and exit codes, run it on a schedule with cron, and build a small health check that would have raised the alarm on 31 August.25 min

10Final ProjectPlan your final project, a full investigation of Tallybook's web server from its logs and command output, with a timeline, findings, fixes and the scripts that would have caught each problem.20 min

Final assessmentPass it (60% or more) to earn the Linux and Networking Basics course completion badge.