SCAR-iT/LWM-Linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Added link to kernel.org - Moves bash into Ch.2 - fixed codeblocks Ch.3

Browse Source
This commit is contained in:
ganome 2024-09-04 11:56:52 -06:00
parent 9fffd6aa28
commit 859e8c3603
Signed by untrusted user who does not match committer: Ganome
GPG Key ID: 944DE53336D81B83
6 changed files with 127 additions and 259 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

0
03 - Package and Process Management/Basic Shell (Bash).md → 02 - Basic System Operations/Basic Shell (Bash).md
View File

3
03 - Package and Process Management/Basics of Kernel.md
View File

@ -51,4 +51,7 @@ The process of building the kernel from source code after configuration. Kernel
### 11. Kernel Development Model: ### 11. Kernel Development Model:
The Linux kernel follows an open-source development model. Linus Torvalds oversees the project, with numerous contributors worldwide. The Linux kernel follows an open-source development model. Linus Torvalds oversees the project, with numerous contributors worldwide.
### 12. External Sources:
[Linux Kernel](https://kernel.org)
Understanding these aspects of the Linux kernel provides a solid foundation for kernel configuration. It helps in making informed decisions about which components to include or exclude based on your system's requirements. Understanding these aspects of the Linux kernel provides a solid foundation for kernel configuration. It helps in making informed decisions about which components to include or exclude based on your system's requirements.

118
03 - Package and Process Management/Package Management with Yum (RHEL Based).md
View File

@ -7,48 +7,32 @@ Yum (Yellowdog Updater Modified) is the primary package management tool for Red
### 2. Basic Yum Commands ### 2. Basic Yum Commands
- Searching for packages: - Searching for packages:
``` `yum search keyword`
yum search keyword
```
- Getting information about a package: - Getting information about a package:
``` `yum info package_name`
yum info package_name
```
- Installing a package: - Installing a package:
``` `sudo yum install package_name`
sudo yum install package_name
```
- Removing a package: - Removing a package:
``` `sudo yum remove package_name`
sudo yum remove package_name
```
- Updating all packages: - Updating all packages:
``` `sudo yum update`
sudo yum update
```
- Updating a specific package: - Updating a specific package:
``` `sudo yum update package_name`
sudo yum update package_name
```
### 3. Working with Repositories ### 3. Working with Repositories
Yum uses repositories to fetch package information and the packages themselves. Yum uses repositories to fetch package information and the packages themselves.
- Listing enabled repositories: - Listing enabled repositories:
``` `yum repolist`
yum repolist
```
- Listing all repositories (including disabled): - Listing all repositories (including disabled):
``` `yum repolist all`
yum repolist all
```
- Adding a new repository: - Adding a new repository:
Create a .repo file in /etc/yum.repos.d/ with the following structure: Create a .repo file in /etc/yum.repos.d/ with the following structure:
@ -63,99 +47,67 @@ gpgkey=http://repository.url/RPM-GPG-KEY
``` ```
- Enabling/disabling a repository: - Enabling/disabling a repository:
``` - `sudo yum-config-manager --enable repository_id`
sudo yum-config-manager --enable repository_id - `sudo yum-config-manager --disable repository_id`
sudo yum-config-manager --disable repository_id
```
### 4. Managing Package Groups ### 4. Managing Package Groups
Yum can install predefined groups of packages. Yum can install predefined groups of packages.
- Listing available groups: - Listing available groups:
``` `yum group list`
yum group list
```
- Getting info about a group: - Getting info about a group:
``` `yum group info "group_name"`
yum group info "group_name"
```
- Installing a group: - Installing a group:
``` `sudo yum group install "group_name"`
sudo yum group install "group_name"
```
- Removing a group: - Removing a group:
``` `sudo yum group remove "group_name"`
sudo yum group remove "group_name"
```
### 5. Yum Cache Management ### 5. Yum Cache Management
Yum maintains a cache to speed up operations. Yum maintains a cache to speed up operations.
- Cleaning all cached packages and metadata: - Cleaning all cached packages and metadata:
``` `sudo yum clean all`
sudo yum clean all
```
- Cleaning only cached packages: - Cleaning only cached packages:
``` `sudo yum clean packages`
sudo yum clean packages
```
- Cleaning only cached metadata: - Cleaning only cached metadata:
``` `sudo yum clean metadata`
sudo yum clean metadata
```
### 6. Advanced Yum Features ### 6. Advanced Yum Features
- Downloading a package without installing: - Downloading a package without installing:
``` `yumdownloader package_name`
yumdownloader package_name
```
- Installing a local RPM package with Yum (to resolve dependencies): - Installing a local RPM package with Yum (to resolve dependencies):
``` `sudo yum localinstall package_name.rpm`
sudo yum localinstall package_name.rpm
```
- Checking for available updates: - Checking for available updates:
``` `yum check-update`
yum check-update
```
- Listing installed packages: - Listing installed packages:
``` `yum list installed`
yum list installed
```
- Listing available packages: - Listing available packages:
``` `yum list available`
yum list available
```
### 7. Yum History ### 7. Yum History
Yum keeps a history of transactions, allowing you to undo or redo actions. Yum keeps a history of transactions, allowing you to undo or redo actions.
- Viewing Yum history: - Viewing Yum history:
``` `yum history list`
yum history list
```
- Undoing a transaction: - Undoing a transaction:
``` `sudo yum history undo transaction_id`
sudo yum history undo transaction_id
```
- Redoing a transaction: - Redoing a transaction:
``` `sudo yum history redo transaction_id`
sudo yum history redo transaction_id
```
### 8. Yum Configuration ### 8. Yum Configuration
@ -176,30 +128,20 @@ Yum's functionality can be extended with plugins. Some useful plugins include:
- yum-plugin-versionlock: Locks specified packages to a particular version - yum-plugin-versionlock: Locks specified packages to a particular version
To install a plugin: To install a plugin:
``` `sudo yum install plugin_name`
sudo yum install plugin_name
```
### 10. Troubleshooting ### 10. Troubleshooting
If you encounter issues with Yum, try these steps: If you encounter issues with Yum, try these steps:
- Clear the Yum cache: - Clear the Yum cache:
``` `sudo yum clean all`
sudo yum clean all
```
- Rebuild the Yum cache: - Rebuild the Yum cache:
``` `sudo yum makecache`
sudo yum makecache
```
- Check for conflicting transactions: - Check for conflicting transactions:
``` `sudo yum-complete-transaction --cleanup-only`
sudo yum-complete-transaction --cleanup-only
```
- Verify the package database: - Verify the package database:
``` `sudo yum check`
sudo yum check
```

56
03 - Package and Process Management/Package Management with apt-get (Debian Based).md
View File

@ -8,9 +8,7 @@
Before installing or upgrading packages, it's important to update your local package lists: Before installing or upgrading packages, it's important to update your local package lists:
```bash `sudo apt-get update`
sudo apt-get update
```
This command synchronizes your package lists with the repositories. This command synchronizes your package lists with the repositories.
@ -18,73 +16,53 @@ This command synchronizes your package lists with the repositories.
To upgrade all installed packages to their latest versions: To upgrade all installed packages to their latest versions:
```bash `sudo apt-get upgrade`
sudo apt-get upgrade
```
For a more aggressive upgrade that might remove obsolete packages: For a more aggressive upgrade that might remove obsolete packages:
```bash `sudo apt-get dist-upgrade`
sudo apt-get dist-upgrade
```
### 4. Installing Packages ### 4. Installing Packages
To install a new package: To install a new package:
```bash `sudo apt-get install package_name`
sudo apt-get install package_name
```
You can install multiple packages at once: You can install multiple packages at once:
```bash `sudo apt-get install package1 package2 package3`
sudo apt-get install package1 package2 package3
```
### 5. Removing Packages ### 5. Removing Packages
To remove a package: To remove a package:
```bash `sudo apt-get remove package_name`
sudo apt-get remove package_name
```
To remove the package along with its configuration files: To remove the package along with its configuration files:
```bash `sudo apt-get purge package_name`
sudo apt-get purge package_name
```
### 6. Searching for Packages ### 6. Searching for Packages
To search for a package: To search for a package:
```bash `apt-cache search keyword`
apt-cache search keyword
```
### 7. Displaying Package Information ### 7. Displaying Package Information
To show detailed information about a package: To show detailed information about a package:
```bash `apt-cache show package_name`
apt-cache show package_name
```
### 8. Cleaning Up ### 8. Cleaning Up
To remove unnecessary packages: To remove unnecessary packages:
```bash `sudo apt-get autoremove`
sudo apt-get autoremove
```
To clear out the local repository of retrieved package files: To clear out the local repository of retrieved package files:
```bash `sudo apt-get clean`
sudo apt-get clean
```
### 9. Handling Dependencies ### 9. Handling Dependencies
@ -98,23 +76,17 @@ Package sources are defined in `/etc/apt/sources.list` and in files under `/etc/
To prevent a package from being automatically upgraded: To prevent a package from being automatically upgraded:
```bash `sudo apt-mark hold package_name`
sudo apt-mark hold package_name
```
To remove the hold: To remove the hold:
```bash `sudo apt-mark unhold package_name`
sudo apt-mark unhold package_name
```
### 12. Simulating Operations ### 12. Simulating Operations
You can simulate operations without actually performing them using the `-s` flag: You can simulate operations without actually performing them using the `-s` flag:
```bash `sudo apt-get -s install package_name`
sudo apt-get -s install package_name
```
This is useful for seeing what would happen without making any changes. This is useful for seeing what would happen without making any changes.

161
03 - Package and Process Management/Proccess Monitoring and Management.md
View File

@ -1,193 +1,148 @@
# Process Monitoring and Management in Linux # Process Monitoring and Management in Linux
### 1. Viewing Running Processes ## 1. Viewing Running Processes
Let's start with the basic commands to view running processes: Let's start with the basic commands to view running processes:
- ps - Process Status ### ps - Process Status
The 'ps' command provides a snapshot of current processes. The 'ps' command provides a snapshot of current processes.
Basic usage: Basic usage:
``` `ps
ps
```
Common options: Common options:
- `ps aux`: Shows all processes for all users - `-aux`: Shows all processes for all users
- `ps -ef`: Similar to aux, but in a different format - `-ef`: Similar to aux, but in a different format
- `ps lax`: Provides more detailed information - `-lax`: Provides more detailed information
- top - Table of Processes ### top - Table of Processes
'top' provides a real-time, dynamic view of running processes. 'top' provides a real-time, dynamic view of running processes.
Basic usage: Basic usage:
``` `top`
top
```
In top, you can use: In top, you can use:
- 'q' to quit - 'q' to quit
- 'k' to kill a process (you'll be prompted for the PID) - 'k' to kill a process (you'll be prompted for the PID)
- 'r' to renice (change priority) of a process - 'r' to renice (change priority) of a process
- htop - Interactive Process Viewer ### htop - Interactive Process Viewer
'htop' is an improved version of 'top' with a more user-friendly interface. 'htop' is an improved version of 'top' with a more user-friendly interface.
Install it (if not already installed): Install it (if not already installed):
``` - `sudo apt install htop` # For Debian/Ubuntu
sudo apt install htop # For Debian/Ubuntu - `sudo yum install htop` # For CentOS/RHEL
sudo yum install htop # For CentOS/RHEL
```
Run it: Run it:
``` `htop`
htop
```
### 2. Process Management ## 2. Process Management
- kill - Terminate a Process ### kill - Terminate a Process
The 'kill' command sends a signal to a process, by default the TERM signal. The 'kill' command sends a signal to a process, by default the TERM signal.
Basic usage: Basic usage:
``` `kill PID`
kill PID
```
Common signals: Common signals:
- SIGTERM (15): Graceful termination - SIGTERM (15): Graceful termination
- SIGKILL (9): Forceful termination - SIGKILL (9): Forceful termination
Example: Example:
``` `kill -9 1234`
kill -9 1234
```
- killall - Kill Processes by Name ### killall - Kill Processes by Name
'killall' allows you to kill all processes with a given name. 'killall' allows you to kill all processes with a given name.
Example: Example:
``` `killall firefox`
killall firefox
```
- pkill - Kill Processes Based on Name and Other Attributes ### pkill - Kill Processes Based on Name and Other Attributes
'pkill' is more flexible than killall, allowing you to kill processes based on various attributes. 'pkill' is more flexible than killall, allowing you to kill processes based on various attributes.
Example: Example:
``` `pkill -u username firefox`
pkill -u username firefox
```
- nice and renice - Adjust Process Priority ### nice and renice - Adjust Process Priority
'nice' starts a process with a specified priority, while 'renice' changes the priority of a running process. 'nice' starts a process with a specified priority, while 'renice' changes the priority of a running process.
Nice values range from -20 (highest priority) to 19 (lowest priority). Nice values range from -20 (highest priority) to 19 (lowest priority).
Example: Example:
``` - `nice -n 10 command` # Start 'command' with lower priority
nice -n 10 command # Start 'command' with lower priority - `renice -n 5 -p PID` # Change priority of running process
renice -n 5 -p PID # Change priority of running process
```
### 3. Background and Foreground Processes ## 3. Background and Foreground Processes
- Start a process in the background: ### Start a process in the background:
``` `command &`
command &
```
- Move a running process to the background: ### Move a running process to the background:
Press Ctrl+Z Press Ctrl+Z
- Bring a background process to the foreground: ### Bring a background process to the foreground:
``` `fg %job_number`
fg %job_number
```
- List background jobs: ### List background jobs:
``` `jobs`
jobs
```
### 4. Advanced Monitoring Tools ## 4. Advanced Monitoring Tools
- iotop - I/O Monitoring ### iotop - I/O Monitoring
'iotop' shows I/O usage by processes. 'iotop' shows I/O usage by processes.
Install: Install:
``` - `sudo apt install iotop # For Debian/Ubuntu`
sudo apt install iotop # For Debian/Ubuntu - `sudo yum install iotop # For CentOS/RHEL`
sudo yum install iotop # For CentOS/RHEL
```
Run: Run:
``` `sudo iotop`
sudo iotop
```
- nethogs - Network Monitoring ### nethogs - Network Monitoring
'nethogs' shows network usage by process. 'nethogs' shows network usage by process.
Install: Install:
``` - `sudo apt install nethogs` # For Debian/Ubuntu
sudo apt install nethogs # For Debian/Ubuntu - `sudo yum install nethogs` # For CentOS/RHEL
sudo yum install nethogs # For CentOS/RHEL
```
Run: Run:
``` `sudo nethogs`
sudo nethogs
```
- lsof - List Open Files ### lsof - List Open Files
'lsof' lists open files and the processes using them. 'lsof' lists open files and the processes using them.
Example (list all network connections): Example (list all network connections):
``` `sudo lsof -i`
sudo lsof -i
```
### 5. System Monitoring ## 5. System Monitoring
- free - Display Amount of Free and Used Memory ### free - Display Amount of Free and Used Memory
``` `free -h` # -h for human-readable format
free -h # -h for human-readable format
```
- vmstat - Report Virtual Memory Statistics ### vmstat - Report Virtual Memory Statistics
``` `vmstat 1` # Report every second
vmstat 1 # Report every second
```
- iostat - Report CPU Statistics and I/O Statistics ### iostat - Report CPU Statistics and I/O Statistics
``` `iostat 1` # Report every second
iostat 1 # Report every second
```
### 6. Process Tracking and Analysis ## 6. Process Tracking and Analysis
- strace - Trace System Calls and Signals ### strace - Trace System Calls and Signals
'strace' is useful for diagnosing problems with processes. 'strace' is useful for diagnosing problems with processes.
Example: Example:
``` `strace command`
strace command
```
- ltrace - Library Call Tracer ### ltrace - Library Call Tracer
'ltrace' is similar to strace but for library calls. 'ltrace' is similar to strace but for library calls.
Example: Example:
``` `ltrace command`
ltrace command
```
### 7. Continuous Monitoring with watch ## 7. Continuous Monitoring with watch
The 'watch' command allows you to run any command periodically, showing output in fullscreen. The 'watch' command allows you to run any command periodically, showing output in fullscreen.
Example (update process list every 2 seconds): Example (update process list every 2 seconds and look at top 5 lines of output):
``` - `watch -n 2 'ps aux | sort -nrk 3,3 | head -n 5'`
watch -n 2 'ps aux | sort -nrk 3,3 | head -n 5'
```

46
03 - Package and Process Management/Understanding and Using SystemD.md
View File

@ -1,10 +1,10 @@
# Understanding and Using SystemD # Understanding and Using SystemD
### 1. Introduction to systemd ## 1. Introduction to systemd
systemd is an init system and system manager that has become the standard for many Linux distributions. It was designed to overcome limitations in the traditional SysV init system, providing faster boot times, dependency-based service control, and a unified interface for managing system services. systemd is an init system and system manager that has become the standard for many Linux distributions. It was designed to overcome limitations in the traditional SysV init system, providing faster boot times, dependency-based service control, and a unified interface for managing system services.
### 2. Core Concepts ## 2. Core Concepts
- Units: The basic building blocks of systemd. Units can represent services, devices, mount points, and more. - Units: The basic building blocks of systemd. Units can represent services, devices, mount points, and more.
- Dependencies: systemd manages relationships between units, ensuring they start in the correct order. - Dependencies: systemd manages relationships between units, ensuring they start in the correct order.
@ -12,7 +12,7 @@ systemd is an init system and system manager that has become the standard for ma
- Sockets: Allow for service activation on demand. - Sockets: Allow for service activation on demand.
- Timers: Provide cron-like functionality for scheduling tasks. - Timers: Provide cron-like functionality for scheduling tasks.
### 3. Unit Files ## 3. Unit Files
Unit files are configuration files that define how systemd should manage a unit. They are typically located in /etc/systemd/system/ or /usr/lib/systemd/system/. Unit files are configuration files that define how systemd should manage a unit. They are typically located in /etc/systemd/system/ or /usr/lib/systemd/system/.
@ -31,23 +31,22 @@ Restart=always
WantedBy=multi-user.target WantedBy=multi-user.target
``` ```
### 4. Basic systemd Commands ## 4. Basic systemd Commands
- systemctl: The main command for interacting with systemd - systemctl: The main command for interacting with systemd
- journalctl: Used for viewing logs - journalctl: Used for viewing logs
- systemd-analyze: Analyzes system boot-up performance - systemd-analyze: Analyzes system boot-up performance
Common systemctl commands: Common systemctl commands:
``` - `systemctl start service-name`
systemctl start service-name - `systemctl stop service-name`
systemctl stop service-name - `systemctl restart service-name`
systemctl restart service-name - `systemctl status service-name`
systemctl status service-name - `systemctl enable service-name`
systemctl enable service-name - `systemctl disable service-name`
systemctl disable service-name
```
### 5. Managing Services
## 5. Managing Services
To create a new service: To create a new service:
1. Create a unit file in /etc/systemd/system/ (e.g., myservice.service) 1. Create a unit file in /etc/systemd/system/ (e.g., myservice.service)
@ -55,7 +54,7 @@ To create a new service:
3. Reload the systemd manager: `systemctl daemon-reload` 3. Reload the systemd manager: `systemctl daemon-reload`
4. Start and enable the service: `systemctl start myservice && systemctl enable myservice` 4. Start and enable the service: `systemctl start myservice && systemctl enable myservice`
### 6. System Boot and Target Units ## 6. System Boot and Target Units
systemd uses target units to manage the boot process. Key targets include: systemd uses target units to manage the boot process. Key targets include:
- poweroff.target - poweroff.target
@ -64,11 +63,9 @@ systemd uses target units to manage the boot process. Key targets include:
- graphical.target - graphical.target
To change the default target: To change the default target:
``` `systemctl set-default graphical.target`
systemctl set-default graphical.target
```
### 7. Logging with journald ## 7. Logging with journald
journald is systemd's logging system. Key features: journald is systemd's logging system. Key features:
- Collects messages from the kernel, services, and applications - Collects messages from the kernel, services, and applications
@ -76,13 +73,12 @@ journald is systemd's logging system. Key features:
- Supports structured logging - Supports structured logging
Basic journalctl usage: Basic journalctl usage:
``` - `journalctl -u service-name` # View logs for a specific service
journalctl -u service-name # View logs for a specific service - `journalctl -f` # Follow new log entries
journalctl -f # Follow new log entries - `journalctl --since "1 hour ago"` # View recent logs
journalctl --since "1 hour ago" # View recent logs
```
### 8. Advanced Features
## 8. Advanced Features
- Socket Activation: Services start on-demand when a client connects to their socket. - Socket Activation: Services start on-demand when a client connects to their socket.
- Resource Control: Limit CPU, memory, and other resources for services. - Resource Control: Limit CPU, memory, and other resources for services.
@ -96,7 +92,7 @@ CPUQuota=20%
MemoryLimit=100M MemoryLimit=100M
``` ```
### 9. Troubleshooting ## 9. Troubleshooting
- Check service status: `systemctl status service-name` - Check service status: `systemctl status service-name`
- View recent logs: `journalctl -u service-name -n 50 --no-pager` - View recent logs: `journalctl -u service-name -n 50 --no-pager`