added gitignore.md under git/concepts/gitignore (#6047)

* initial commit, added gitignore.md under git/concepts/gitignore

* added new entry on the Multilevel Inheritance term under C++

* Revert "added new entry on the Multilevel Inheritance term under C++"

This reverts commit 21029b3.

* new concept entry gitignore.md

* Update gitignore.md

* minor fixes

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content/git/concepts/gitignore/gitignore.md

@@ -0,0 +1,76 @@
+---
+Title: '.gitignore'
+Description: 'A configuration file that instructs Git to ignore specific files and directories when tracking changes in a repository.'
+Subjects:
+  - 'Code Foundations'
+  - 'Developer Tools'
+Tags:
+  - 'Git'
+  - 'GitHub'
+  - 'Version Control'
+CatalogContent:
+  - 'learn-git'
+  - 'learn-the-command-line'
+---
+
+A **.gitignore** file specifies the files and directories that Git should ignore when tracking changes in a repository. This is particularly useful for excluding build artifacts, temporary files, dependencies, and sensitive information from version control. The .gitignore file should be located in the root directory of a repository.
+
+## Common .gitignore patterns
+
+Below are common patterns typically included in .gitignore files:
+
+```plaintext
+# Ignore node modules directory
+node_modules/
+
+# Ignore build output directories
+dist/
+build/
+
+# Ignore environment files
+.env
+.env.local
+
+# Ignore log files
+*.log
+
+# Ignore system files
+.DS_Store
+Thumbs.db
+
+# Ignore IDE specific files
+.idea/
+.vscode/
+*.sublime-project
+*.sublime-workspace
+```
+
+## Creating a .gitignore file
+
+Step 1: Create a new .gitignore file in the repository's root directory:
+
+```shell
+touch .gitignore
+```
+
+Step 2: Open the file in the preferred text editor and specify the files and directories to ignore:
+
+```shell
+# Open with VS Code
+code .gitignore
+
+# Open with Vim
+vim .gitignore
+```
+
+> **Note:** Wildcards like '\*' can be used for pattern matching and '#' for comments in the .gitignore file.
+
+## Common .gitignore rules
+
+1. Specific file: `filename.txt`
+2. File pattern: `*.log`
+3. Directory: `node_modules/`
+4. Nested directory: `**/logs/`
+5. Negation (don't ignore): `!important.log`
+
+> **Note:** If ignored files have already been committed, remove them from Git's tracking using `git rm --cached <file>` before .gitignore takes effect.