yum doc

Linux/LPIC1/6-yum.md

@@ -0,0 +1,156 @@
+# 🍽️ Managing Packages with `yum` on RHEL/CentOS
+
+`yum` (Yellowdog Updater, Modified) is the traditional package manager for RPM-based Linux distributions such as **Red Hat Enterprise Linux (RHEL)** and **CentOS**. Below is a breakdown of commonly used `yum` commands, categorized and explained in detail.
+
+---
+
+## 🔄 1. Updating the System
+
+### `yum update`
+
+Fetches the latest package metadata and installs available updates for all packages currently installed on the system.
+
+```bash
+yum update
+```
+
+---
+
+### `yum upgrade`
+
+Performs the same function as `yum update`. In older versions of `yum`, `upgrade` was used for more aggressive upgrades, but in recent versions, they are functionally equivalent.
+
+```bash
+yum upgrade
+```
+
+---
+
+## 📥 2. Installing and Reinstalling Packages
+
+### `yum install <pkg-name>`
+
+Installs a new package along with any required dependencies.
+
+```bash
+yum install <pkg-name>
+```
+
+---
+
+### `yum reinstall <pkg-name>`
+
+Reinstalls an already installed package, which is useful if system files have been corrupted or modified.
+
+```bash
+yum reinstall <pkg-name>
+```
+
+---
+
+### `yum localinstall <file-dir>`
+
+Installs a `.rpm` package from a local file path while resolving dependencies using remote repositories.
+
+```bash
+yum localinstall <file-dir>
+```
+
+---
+
+## ❌ 3. Removing Packages
+
+### `yum remove <pkg-name>`
+
+Uninstalls the specified package from the system, including any dependencies no longer required.
+
+```bash
+yum remove <pkg-name>
+```
+
+---
+
+## 🔍 4. Querying and Searching
+
+### `yum list`
+
+Lists all available, installed, and updatable packages.
+
+```bash
+yum list
+```
+
+---
+
+### `yum info <pkg>`
+
+Displays detailed information about the specified package, including version, repository, summary, and description.
+
+```bash
+yum info <pkg>
+```
+
+---
+
+### `yum search`
+
+Searches for a keyword in package names and descriptions. Add the search term to complete the command.
+
+```bash
+yum search <keyword>
+```
+
+Example:
+
+```bash
+yum search python
+```
+
+---
+
+### `yum deplist <pkg>`
+
+Shows the list of dependencies for a given package.
+
+```bash
+yum deplist <pkg>
+```
+
+---
+
+## 🕓 5. Package History and Transactions
+
+### `yum history`
+
+Displays a history of all yum transactions (installs, updates, removals), which can be reviewed or undone if needed.
+
+```bash
+yum history
+```
+
+---
+
+## 💾 6. Downloading Packages (Without Installing)
+
+### `yum download <pkg>`
+
+Downloads an RPM package file without installing it. Useful for transferring or offline installations. Requires the `yum-utils` package.
+
+```bash
+yum download <pkg>
+```
+
+> 💡 **Note:** If you get an error, try installing `yum-utils`:
+>
+> ```bash
+> yum install yum-utils
+> ```
+
+---
+
+## ✅ Final Notes
+
+* `yum` has been replaced by `dnf` in newer distributions (e.g., RHEL 8+), but still widely used in older systems.
+* Always run `yum update` before installing new packages.
+* Combine with `yum history` to review or undo changes when troubleshooting.
+