Diff Tools Beyond git diff: When You Need to Compare More Than Source Code

Every developer knows git diff . But the need to compare two pieces of text extends far beyond version-controlled source code. Configuration files from two servers. API responses before and after a change. Database schemas across environments. SQL query outputs. Log files from two different runs. For these cases, you need a diff tool that works with arbitrary text, not just git-tracked files. How diff algorithms work The core algorithm behind most diff tools is the Longest Common Subsequence (LCS) problem. Given two sequences, find the longest subsequence present in both. Everything not in the LCS is either an addition or a deletion. The classic Myers diff algorithm (used by git) solves this in O(ND) time, where N is the total length and D is the number of differences. For files that are mostly similar (the common case), this is fast. The output format matters: Unified diff : Shows changes with context lines. Lines starting with - are removed, + are added. This is what git diff produce