C# .gitignore template

The first thing you notice is the bracket notation: [Bb]in, [Oo]bj, [Dd]ebug, [Rr]elease. Git patterns are case sensitive, but Windows filesystems are not, so a project created by one tool may produce bin while another produces Bin, and both are the same directory as far as Windows is concerned. The character class matches either, which is why this template is full of them rather than plain lowercase names.

bin and obj are the two output directories every project produces. obj holds intermediate state including the restored package graph and generated assembly info; bin holds the compiled assemblies and everything copied alongside them for a run. Both are rebuilt from the project file, and obj in particular embeds absolute paths from the restore step.

The NuGet block covers *.nupkg and *.snupkg, which are the package and symbol package you produce when packing a library, plus the packages directory used by the older package management style. Modern projects restore into a global cache outside the repository, so that directory may never appear, but the rule is cheap insurance for a solution that has not been migrated.

The Visual Studio rules are about per developer state rather than build output. .vs is the editor's own working directory. *.suo holds solution user options such as which files you had open. *.user and *.userosscache record project settings scoped to one person, and *.sln.docstates records document layout. Committing any of them means every teammate fights over your window arrangement.

[Tt]est[Rr]esult* covers the output directory that test runs produce. What the template does not cover is a local application settings file holding a connection string, which is the usual place a C# project leaks a database password. The convention that avoids it is keeping development secrets in the user secrets store, which lives in your profile directory rather than in the repository, so there is nothing to ignore in the first place.