Linux
Linux sed:Edit Streams Without Opening an Editor
Hands-on sed recipes for everyday work — substitute text, delete lines, edit files in place, and reshape output in pipelines.
Read MorePosts (238+)
Browse the full archive. Use topics in the sidebar to explore by tag.
June 2026
Java
Set:Uniqueness Without Scanning the List
Use Set when uniqueness is the job — equals-based membership, no indexes, and why List.contains is the wrong uniqueness type.
Read MoreData Structures
Binary Search Trees:Ordered Trees That Go Lopsided Under Sorted Input
A BST keeps left < node < right so search is O(height). Why already-sorted inserts become a linked list, and what that does to the bill.
Read MoreJava
List:Index, SubList, and Random Access as a Type
Use List as an indexed contract — get/set, subList views, sort/replaceAll, and RandomAccess — without treating every List like an ArrayList.
Read MoreData Structures
Binary Trees:Shape, Traversals, and What “Balanced” Even Means
A binary tree is a hierarchical layout: left, right, parent. Height vs size, preorder inorder postorder and level-order as operations of the shape, and what balanced actually promises.
Read MoreData Structures
Sets:Uniqueness Without Scanning the List
The set ADT is unique membership. HashSet delivers it with a hash table; List.contains is a scan. When TreeSet belongs instead, and what you lose (order).
Read MoreJava
Collection and Iterator:The Contract Every List and Set Shares
Use Collection and Iterator as the shared contract — optional operations, fail-fast iteration, bulk methods, and removeIf — before you pick ArrayList or HashSet.
Read MoreLinux
Linux ps and pgrep:Find Running Processes
Hands-on ps and pgrep recipes — locate processes by PID, user, memory footprint, or command path without a live monitor.
Read MoreJava
Collections Roadmap:Pick the JDK Type for the Job You Have
The Java Collections Framework as a map: hierarchy, glossary, a nulls-order-threads matrix, and a living catalog of every post in this series.
Read More